I didn't answer because I didn't recognize the number.  They did leave a message stating that they had received notice that there was a case they had that had my name attached to it.  They did not state what it was but that if I wanted to know what it was about that I could call a toll free number to find out and gave me a reference number.  No company name was given in the message.  I believe it was a phishing expedition or debt collector trying to collect something not due.
When I called the number back (not the toll free number) and got a recorded message to leave my name, phone number and case number.