If you receive a subpeona to show up in court regarding a credit card debt you could not pay what should you do?

It would be advisable to make the court appearance. If she does not appear in court she will lose by default. In which case she may not be able claim some of the state exemptions. Since I do not know what your state of residency is, I am sorry I cannot give you some idea of what those exemptions are. It would be preferable for her to have legal representation.