By Rafael Vicario González, lawyer in Barcelona, graduate in Law from the Universitat de Barcelona, member of the Il·lustre Col·legi de l’Advocacia de Barcelona and lawyer at Bufet Gómez Ferré.
When a client fails to pay what they owe, the recommended first step before going to court is to send a formal debt collection letter. A well-drafted letter can resolve the debt without litigation —and in many cases it does—. But since 3 April 2025, Organic Law 1/2025 adds a new mandatory requirement: the letter must also meet the standards of the Adequate Means of Dispute Resolution (MASC), because without evidencing this prior step, the court will not admit the claim. At BUFET GÓMEZ FERRÉ we are specialist debt recovery lawyers in Barcelona and in this article we explain how to draft the letter correctly, what MASC is, and when to use the confidential binding offer.
What is a debt collection letter and what is it used for?
A debt collection letter is a formal communication sent by the creditor to the debtor demanding payment of an overdue and unpaid amount. Unlike a simple payment reminder, the formal collection letter has three immediate legal effects:
- Evidentiary value: it proves that the creditor made a diligent attempt to collect before resorting to legal proceedings.
- Interruption of the statute of limitations: under article 1973 of the Civil Code, an extrajudicial claim interrupts the limitation period, restarting the clock.
- MASC requirement compliance: since 3 April 2025 (LO 1/2025), a correctly drafted letter evidences the extrajudicial resolution attempt required before any civil or commercial lawsuit.
Sending this letter is the first step of any serious debt management protocol. In many cases, a well-drafted letter alone is enough to prompt the debtor to pay without any court proceedings.
Essential elements of a debt collection letter
For the letter to be effective, legally valid and compliant with the MASC requirement, it must include:
- Creditor details: full name or company name, address, tax ID and contact details.
- Debtor details: full name or company name and address.
- Detailed description of the debt: subject matter, total amount, due date and supporting documents.
- Attached documentation: copies of unpaid invoices, the contract if any, and relevant prior communications.
- Payment deadline: a minimum of one month from receipt.
- Willingness to reach an amicable resolution: key element for MASC compliance. The letter must express openness to negotiate, not merely demand payment.
- Notice of legal action: stating that if payment is not made within the deadline, legal proceedings will be initiated, with costs and interest borne by the debtor.
- Place, date and signature.
Debt collection letter template
Below is a model updated to LO 1/2025, adaptable to companies or individuals:
[Place], [date]
Attention: [Name / Company name of the debtor]
Address: [Debtor’s address]
Dear [Surname / Legal representative]:
By means of this letter, [Creditor’s company name], with Tax ID [XXXXXXXXX] and registered address at [address], hereby addresses you with this CONFIDENTIAL BINDING OFFER regarding the following outstanding debt:
- Subject: [description of service / product supplied]
- Total amount: [XXXX.XX €]
- Due date: [DD/MM/YYYY] · Invoice no(s): [XXXX]
Despite the agreed payment deadline having passed without us receiving payment, the amount remains outstanding as of today.
Pursuant to Organic Law 1/2025, of 2 January, on Adequate Means of Dispute Resolution (MASC), by means of this CONFIDENTIAL BINDING OFFER we formally propose to initiate direct negotiations to resolve this dispute amicably. We are open to exploring payment arrangements that facilitate settlement of the debt.
We grant you a period of one month from receipt of this letter to contact us or to pay the outstanding amount in full.
If the deadline passes without a response or agreement, and having fulfilled the prior negotiation requirement of LO 1/2025, we will proceed to take the appropriate legal action to recover the debt judicially, plus default interest and costs, which shall be borne by you.
In accordance with art. 6.1 of Organic Law 1/2025, we inform you that you may engage legal counsel for these offer-mediation-negotiation proceedings, and that your failure to participate may be taken into account by the court when awarding costs.
This communication constitutes a prior extrajudicial claim for the purposes of interrupting the statute of limitations, awarding procedural costs in the event of submission or rejected opposition, and evidencing an outstanding debt claim.
We remain at your disposal at [contact details].
Yours faithfully,
[Full name] · [Position] · [Company name]
Attachments: invoice(s) no. [XXXX]; [contract if applicable]; [delivery notes if applicable].
This is a model letter meeting the minimum requirements of LO 1/2025. Each case may require adjustments. If in doubt, contact us with no obligation.
Burofax vs. ordinary letter: when should you use each?
A common question is whether an email or ordinary letter is sufficient, or whether a burofax is required:
| Letter / ordinary email | Burofax (proof of receipt + content certification) | |
|---|---|---|
| Cost | Minimal | Higher (postal operator) |
| Evidentiary value | Limited (hard to prove receipt) | High: proves sending, receipt and exact content |
| Interrupts limitation period | Yes, but may be challenged | Yes, conclusively |
| Valid as MASC | Only with conclusive proof of receipt | Yes, fully valid |
| Recommended when | Informal reminders | Significant debt or anticipated litigation |
⚖️Lawyer's advice: For debts above €1,000 or when litigation is anticipated, always send the burofax with proof of receipt and content certification. This interrupts the statute of limitations unequivocally and evidences the MASC requirement in a single step.
Does a debt collection letter interrupt the statute of limitations?
Yes, but with important nuances. Article 1973 of the Civil Code establishes that the statute of limitations is interrupted by an extrajudicial claim by the creditor. For this to be conclusive, three requirements must be met:
- Received: the debtor must have received the claim.
- Clear intention to collect: it must identify the specific debt being claimed.
- Identifiable: creditor, debtor and debt must be clearly identified.
A simple email without read confirmation may not be sufficient if the debtor denies receipt. The burofax with content certification is the safest instrument.
📌Limitation periods vary depending on the type of debt. For commercial debts between companies, the general period is 5 years (art. 1964 CC). More info → When does a judicially claimed debt become statute-barred?
The debt collection letter as MASC: the new pre-litigation obligation
The Organic Law 1/2025, of 2 January (in force since 3 April 2025) has introduced a fundamental change: before filing any civil or commercial claim, the creditor must prove that they attempted to resolve the dispute through an Adequate Means of Dispute Resolution (MASC). Without this step, the court will reject the claim (art. 403.2 CPC).
The good news is that a well-drafted burofax can simultaneously fulfil its traditional function and the MASC requirement. The recognised MASC types are:
| Type of MASC | Description | Recommended for debts? |
|---|---|---|
| Mediation | With an accredited mediator registered with the Ministry of Justice. Neutral intervention to facilitate agreement. | ⚠️ Slower and costlier |
| Conciliation | A third party brings the parties closer. Options: private, notarial, registry-based or before a Court Clerk or Justice of the Peace. | ⚠️ Specific cases |
| Direct negotiation | The parties or their lawyers negotiate without a formal neutral third party. A well-drafted burofax is the most common route. | ✅ Most common |
| Confidential binding offer | Specific mechanism under art. 17 LO 1/2025. | ✅ For high amounts |
| Independent expert opinion | When the dispute requires specialised technical assessment. | ⚠️ Technical disputes |
The confidential binding offer: when and how to use it
The confidential binding offer (art. 17 LO 1/2025) is the most strategic MASC for high-value debts:
- The creditor sends the debtor a specific, quantified proposal (e.g.: “I accept €9,000 instead of €11,000 if payment is made within one month”).
- If the debtor accepts, the agreement is binding on both parties.
- If they reject or do not respond, the creditor can go straight to court.
- The content is strictly confidential: in court only the fact of sending and receiving is proven, not what was offered. The content can only be disclosed in the costs assessment phase.
Key advantage on costs: if the debtor unreasonably rejects a fair offer and loses the case, that rejection may weigh against them in the costs award (amended art. 394 CPC), and they may even forfeit the costs they would otherwise have been entitled to.
What happens if the MASC requirement is not evidenced?
⚠️Since April 2025: If a lawsuit is filed without proving the prior MASC, the court will reject it (art. 403.2 CPC). The defect is not always curable. Make sure your letter meets the requirements before sending it.
The consequences of filing a claim without fulfilling the MASC requirement are serious:
- Rejection of the claim (art. 403.2 CPC): the court will refuse it outright.
- Not always curable: if no MASC was attempted at all, the rejection is final.
- Risk of limitation: while the defect is being remedied, the limitation period keeps running.
- Adverse costs order: a party that unjustifiably rejects MASC may be ordered to pay costs, or even forfeit the costs they would otherwise have been entitled to.
Case study (fictitious example)
- Situation
Estrategia & Proyectos SL, a consulting firm, provided advisory services to an SME for three months totalling €8,500, documented in three invoices. After the payment deadline, the debt remains unpaid.
- Strategy
Advised by Bufet Gómez Ferré, they send a MASC-compliant burofax (confidential binding offer): debt identified, one-month deadline and explicit willingness to negotiate under LO 1/2025. The dispatch reference, proof of receipt and content certification are retained.
- Outcome
The debtor SME, facing imminent legal action, offers to pay in two instalments. Dispute resolved extrajudicially with no court proceedings. One document, two effects: MASC evidenced and debt resolved.
- Conclusion
A well-drafted collection letter remains the most effective first step. With the LO 1/2025 adjustments, it meets the MASC requirement in a single stroke, at no extra cost or delay.
📌Once the MASC has been sent and the deadline has passed, which court procedure is best? → Order for payment vs. ordinary proceedings: which procedure to use to recover a debt
Frequently asked questions
Since 3 April 2025, yes. Organic Law 1/2025 requires evidencing a prior extrajudicial resolution attempt (MASC) before filing any civil or commercial claim. A well-drafted burofax meets this requirement provided it expresses willingness to negotiate and sets a reasonable response deadline. Without this prior step, the court will reject the claim (art. 403.2 CPC). The order-for-payment procedure is also subject to this requirement, except for debts documented in bills of exchange (promissory notes, bills of exchange or cheques).
There is no minimum legal number. One formal collection letter sent by burofax is sufficient to evidence both the extrajudicial attempt and the MASC requirement. What matters is keeping all dispatch documentation: reference number, dated proof of receipt and content certification.
Legally, yes. But ignoring the letter has consequences: the limitation period is interrupted, the letter stands as evidence of the extrajudicial attempt, the creditor can initiate proceedings immediately, and the unjustified rejection of MASC may be viewed negatively in the costs award (amended art. 394 CPC under LO 1/2025).
Free consultation – Specialist debt recovery lawyers in Barcelona
If you have an unpaid invoice or need to send a debt collection letter compliant with LO 1/2025, Bufet Gómez Ferré offers a free consultation to assess your case with no obligation.
As specialist debt recovery lawyers in Barcelona, we manage the entire process: drafting the MASC-compliant burofax, monitoring the deadline, extrajudicial negotiation and, if necessary, full court proceedings through to enforcement. We work on a no-win no-fee basis wherever the viability of the case allows.
Contact us and recover what is yours with maximum efficiency and cost transparency.