You need to be aware that there are quite a few fraudulent debt collection companies preying upon consumers these days. In order to ascertain if this company  is a valid third party debt collection company that has purchased some debt that you are obligated under, I would first do the following:1. write the company a letter seeking a copy of all documents showing an assignment of the debt that it is calling you about.2. ask for copies of all documents showing that you are obligated upon the claimed debt.Until you receive such information, you cannot be expected to make a valid decision on the debt owed as to pay it or not. Do not give the third party debt collection company's representative any personal information about you. Keep a copy of all communication sent to this company for future need and reference.