they called with a a story that they were federal crimes investigation unit a much of b.s.investigating a debt!

I keep getting calls from this number, several times in a day for the last few months.  The recording always says the call is for someone else who does not and has never lived at this number. I have attempted to call the number, no one gets on the line after a female recording comes on with a short message saying they are looking up my account with Nationwide Credit. I dont have any accounts with Nationwide credit. How do I get these people to stop calling me?????

Non stop calling never answers me when I pick up!!! Who is this!!