I just got a call from that number saying my ss was attached to the file.  However, they were trying to find an ex sister in law.  It is collections.   NRG  I told them I havent seen her in years, which is the truth, so they removed me off their list.
The agency name does sound legit because I used to get mail from them a few years ago, so I thought at first, they were looking for me about medical bills or student loan.