How do you prove that a “MASC” (appropriate dispute resolution method) was attempted?

Question

José Manuel Alburquerque · Accepted Answer

The document proving the attempt must be submitted with the claim and the claim must explain how the attempt was made. If a negotiation did take place, a document signed by both parties or the certificate of the mediator or conciliator will do. If the other party did not reply or refused to negotiate, it is enough to prove that they received the invitation, on what date and on what matter. The safest option is a method that also certifies the text sent, such as a “burofax” (a certified letter with proof of content) with acknowledgement of receipt, or a notarial record (“acta notarial”). If you do not know where to find the other party, the law accepts a “declaración responsable” (a formal statement made on your own responsibility) explaining this. What must be submitted The “Ley de Enjuiciamiento Civil”, Spain's Civil Procedure Act, requires the claim to describe the attempt at negotiation and to be accompanied by the document that proves it. The proof depends on how it went: If there was direct negotiation, a document signed by both parties showing their names, the date and the matter, which records that they negotiated in good faith, even if they did not reach an agreement. If a mediator, a conciliator or an expert was involved, the certificate that they issue at the request of either party, including when the other party did not attend. If the other party did not reply or rejected the invitation, a copy of what was sent to them and proof that they received it and of when they received it. If you do not know the other party's address or any way of contacting them, a formal statement in which you explain this. It must be true, because a false statement can result in a fine. The document must show that the negotiation concerned the same thing that is later sought in the claim. An old letter about another matter is not enough. What was said in the negotiation is confidential, so the claim proves that there was an attempt, but does not reveal its content. Which methods are accepted In Barcelona, it is a criterion agreed by the court clerks (“letrados de la Administración de Justicia”), who are the first to examine the claim, that the following methods are valid: Burofax and registered post, if there is a record of the text sent. Email, if there is a record that it was received and of what it said. A notarial record. An electronic method that the parties had agreed on or delivery through a trusted third party that certifies it. It is also a criterion agreed by them that WhatsApp conversations, phone calls and text messages are not valid. According to those same criteria, if the other party refuses to accept the delivery or delivery cannot be proved, it is advisable to attach a formal statement explaining this. In Barcelona, it is a criterion agreed by the civil sections of the “Audiencia Provincial” (the provincial appeal court), since October 2025, that any method that leaves a record of sending and receipt is valid, including WhatsApp, the service provided for these attempts by “Correos” (the Spanish postal service) or an item that the addressee does not collect after a notice has been left. As the claim is reviewed first by the court clerks, the safest course is to use one of the methods they accept. How to do it properly So that the attempt is not disputed later, it is advisable to take care over these details: The letter should genuinely invite the other party to negotiate in good faith and state what the negotiation is about. A mere demand for payment announcing that a claim will be brought is not enough. It should give a deadline for replying and be sent to the address stated in the contract or to the one the other party normally uses. The text sent, any replies received and the proof of sending and delivery should be kept. The attempt should have ended before the claim is filed.