Dear Sir,

Welcome to the belegal forum.

My first advice is that you approach the rental agency and request a copy of your rental contract as you say you have not got it any longer. In the event there was a clause allowing them to change the lock and request eviction due a delay of more than 30 days in the rental fee payment, please note that this clause is NOT legal. Therefore, should they proceed to change the locks while you lived there, I advice you to appoint a solicitor at the earliest to file a report at the relevant authorities. According to law, the eviction process can be started after one day´s delay in the rental payment, though you can oppose, if you paid the due amount, at once. Once you have paid the months´ rent due through opposition, the process will be stopped.

Please click on the following article about how to evict a tenant and you will find all your concerns answered: http://belegal.com/articles/showArticle/spain-tenant-not-paying-rent-spanish-property

Regards,