problems with "casera" (Madrid)

Hi guys,
Today I was moving out and had unexpected problems with my "casera" (landlady). She refused to return all of my fianza (deposit) and instead gave back only 50% of it. She stated that because the 1-year contract was set to expire on Sept. 23 and I moved out on the 16th she didn't have to do it because the contract was broken. However, a long time ago, when I was first considering moving out (there were tons of problems with the apartment and she had to send someone to fix something almost on weekly basis) she said that she doesn't care if I stay or go as long as I give her about 3 weeks' notice before doing so (unfortunately, at this time, I cannot find this anywhere in writing, I believe it was just something she said over the phone). Well, that's exactly what I did this time... and, when I informed her 3 weeks ago about my plan of moving out, she didn't mention a single word about the contract or about refusing to return the fianza... in fact, I specifically asked her when it would be done, and mentioned the specific amount I was expecting (the same I left with her initially) and she simply said that she will need to inspect the apartment once I move out and then return it to me, again, without making any reference to the contract. In fact, the first time she mentioned it was today, after all my furniture was already out of the apartment... Is there anything that I could do? Would it make sense/be worthwhile to go through the rental tribunals?
thanks advance for any input/advice you can provide!