Hello and welcome to the belegal forum,


You have not indicated the type of problems your tenant has been claiming should be fixed, though in the event that these problems existed when she started the tenancy, she should have agreed with you a calendar of repairs and the possible compensation and/or discount on the rental fee for the same. If this was not agreed, and she started her tenancy with full knowledge of the problems, she is in the obligation to pay full rent and supplies from the first day of her tenancy, regardless of subsequent repairs to be done on the property.
Please read the following article that outlines the steps to be followed and aspects to be taken into consideration when you need to start an eviction process:
http://belegal.com/articles/showArticle/spain-tenant-not-paying-rent-spanish-property

Regards,