Finance House

Arizona is where I'm located, FirstUSA is the credit card company, they are located in Delaware.
Situation: Paid off and closed a secured credit card. Was told to expect a check for the original security deposit plus interest accrued. They couldn't tell me the exact amount the check would be, as interest would still compound until the check was actually cut.
Received check which was about 2,000 more than I thought it would be. I happily went to bank and cashed it.
Never heard a word from the bank. Eventually recv'd a normal statement from them which i assumed would indicate my 0.0 balance and that the account was closed.
To my surprise, it instead indicated a charge for the amount of the check, plus over the limit fees! This, on a closed account, which, IMO, no longer existed! (The original credit line was $1,000) In other words, they charged me for the entire check + penalties and 20% interest!!
Now, all morals aside.... is there a precedent for this? Surely banks have made errors in the past, so who's deemed responsible? Incidentally, I only received the erroneous check, never the legitimate one. I am, of course, perfectly willing to let them keep the legit original deposit, lick their wounds, learn from it and eat the 2k they screwed up on. They, of course, don't want to hear any of it. Folks, I'm looking for the LEGAL answers, not necessarily the moral ones...yes, I know what the "right" thing to do is....just curious what the courts would say. Thanks!!!