I was directed by the local attorney general's office that this is a scam. I am not calling them back at a toll number and if they do get me on the phone I will try to get their address to give to the attorney general's office as well as request in writing from them whatever bill they think I owe.
These people call themselves "Investigators" to intimidate the people they are trying to collect a debt from. If you let them know that you know they are just ordinary debt collectors and that you do not believe them about their "Federal Investigations" or their "Federal Warrants", they change their tune quickly. When I was dealing with Steagall and Weinberg I refused to call them investigators. I told them to do what they had to do. That was in july of 2009. No warrants yet!