Excessive charge for carpet stains

I would like to report how I was ripped off by my last landlord in San Antonio/TX.
Upon move-in in March 98 I was charged a non-refundable pet fee of $150 for our dog and another "refundable" security deposit of $400.

In October 98 we had heavy rainfalls in San Antonio and the carpets were soaked with water from the ground. This resulted in multiple stains on the carpet caused by my wood furnitures. At that time I notified the manager several times in person, by phone, and in writing about the water damage. Every time I contacted her I was told that many tenants had experienced the same problems and that they will send somebody to check on the damages and clean the carpets if necessary.

It took approximately 4 weeks until somebody came by and took a look at the carpets but nothing else was done. In fact, the maintenance person told me not to worry about the stains!

In July 99 we moved out and cleaned the carpet as well as possible with a steamcleaner and stain removers but unfortunately some of the stains could not be removed. The landlord assessed the damage at $500 but kept my entire deposit ($550) stating that $50 was a non-refundable processing fee. I complained with a certified letter and they finally were willing to return $50 but did not mention anything about the rest of my deposit!

In my opinion their charges are excessive as the carpets were not new when we moved in and I am curious what you think. If possible, I would like to get my money back.