This is a collection agency, and a bad acting one at that. Do NOT give them any personal information. They will harass the hell out of you even if you have never had a bad account anywhere.
Do yourself a favour if you see this number come up. Don't bother answering. It is only a computer calling and when you try to call back the number, you don't get a person anyway. Should you get a person and give them any information, you are giving them leverage to attack you with. That is the only reason they try to talk to you. The legitimacy or very existence of the debt is a secondary matter!!