Texas. Had a one year lease, $600 security deposit and all was well. Signed renewal, paid an additional, refundable, $200 pet deposit for 2 pets. During second year property was sold to unknown owners, managed by a third party. One day, the AC unit suddenly leaked a huge amount of water from the attic, caving in the ceiling in the hallway, leaving a huge hole (about 2ft X 4ft). Despite my repeated requests, the ceiling was never repaired. Maintenance would always come out, promise to return with a professional, and then not return. After 4 months and several requests in writing, I notified the management company (where I normally paid rent) they had breached our lease by failing to make repairs, and I was exercising my right to move out without penalty.
We cleaned, but the place wasn't spotless when we moved out. We did leave behind some curbside trash (which was normally picked up for free by the city), and the dog damaged the vertical blinds. When requesting my security deposit, the landlord instead sent me a huge bill, including cleaning, trash removal, drywall/contractor repair, and a re-letting fee (even though they didn't relett, and my original lease specifically stated $0 relet fee). They also charged the last 3 months rent that I would have paid, had they made repairs. They only applied the $600 (not $800) security deposit. I disputed.
At the time I received this bill, none of the work had been done (can't they only bill me for ACTUAL damages, not estimates??). A new tenant wanted my old apartment because it was the end unit, the landlord refused to rent it to them (but did rent another unit to the person), saying my old unit needed repairs (failure to mitigate rent damages, even if I did owe them). The bill was not itemized by repair/damage, merely a one or two word comment by each amount. I disputed each item, but also requested further clarification of the damages for which I was being charged. I received no response whatsoever. 7 months later, a collection agency placed an item on my credit reports for this amount, management company shown as creditor.
I live in California now. If they wanted to file suit, would they have to do it in my home state? Or would they do it in Texas? I really am not interested in travelling back to a Texas court for the $800 security deposit. All I want is this item off my credit report, and to be done with the whole mess. Any advice?
Am I right in the way I am reading the law, in the questions above?

