Under the Fair Debt Collections Practices Act, you are entitled to proof of the debt. Under trial court discovery rules, you are also entitled to a copy of the evidence relevant to your case. I don't understand why their own attorney would need to get you to sign a release form to provide the information to you. Normally the attorney should have been sent all of the documentation before he even filed the lawsuit.
You should try filing a Motion to Compel Discovery, asking the court to order the credit card company to turn over the records to you. You could also try filing a Motion to Dismiss
, requesting that the court dismiss the case because the Plaintiff has refused to provide you with the records.
If you are claiming that you never opened the credit account in the first place, you should file an Answer with the court asserting that you are not the person who opened the account. If someone has opened an account in your name, you should go meet with law enforcement to start an investigation over the identity theft. A judge will take your claim of identity theft more seriously if you have taken steps to have the theft prosecuted.
It is hard to know exactly what is going on without reading all the documents related to your case. However, if they want to sue you for a debt then they have the burden of proving the debt exists. You may be able to get a dismissal over their refusal to provide you with the evidence against you.
I would suggest that you go see a local attorney and get some advice about how your judge handles cases like this. If you can't afford to hire an attorney to represent you on the case, you could at least pay one for a consultation to get some ideas on how to present your defense in court. A 30 minute consultation with a lawyer won't cost you that much, but it could make a big difference in the outcome of your case.