Harassment

There is no way to answer your question without more information. Do they leave you messages, does their caller i.d. show who they are. If they haven't left messages and you haven't talked to them how do you know what their purpose is and which card its about. Is it the original creditor or is it a 3rd party debt buyer? As to it being paid off that would seem to indicate you know which card its about. Do you have proof it was paid off? If it was discharged in bankruptcy the attorney who performed your bankruptcy has a duty to follow up for you when you are getting collection calls about anything covered in the bankruptcy.

Preliminary info needed.