Unfortunately, there is nothing you can do with the original creditor because they sold the debt to an outside CA.
You have to confirm that you are contacted by the right company that has your info. You are supposed to get the debt details in your mail within five days after the first call. If you hear nothing, send a DV letter to the company that called you. Your documentation should prove that you are taking care of the matter and want to pay to that company your file is with. This will help you in case you get a court hearing and the problem is not resolved.