I recently got a court letter saying I am being sued for a debt owed on a credit card. I know that I have not used that card for at least 10 years. To be frank I have no way to know if I owe them the money or not.

The suit was not brought by the card company, but someone who claims to have rights to sue me. I know that I have to file an answer in a timely fashion, but what can I do? I do not have any bills (who does after that long). I do not believe that I have had any judgments against me, so how can they sue me without any bills?