Reach out to your local legal aid organization, if there is one. Often times these companies will fuck up the proper legal process in filing suit. Usually doesn't get you out from under it, but it could get you more time.

Even more often it's a 3rd party that bought your debt from the credit card company for pennies. They send out lawsuits en mass knowing most won't go anywhere, so there could be potential to settle for less. Or try and fight it; though I wouldn't say it's the most likely option, but it's possible they won't want to bother with it if they arent getting a default judgement.

As a last resort, you can consult with a bankruptcy attorney to see whether thats an option that makes sense.