Received the same message this morning. The caller was hard to understand but indicated that this was their second attempt to contact me and if I did not call back.... Pretty threatening. Watch out!
Lucky me, it's Saturday, and somehow, I got the call twice, two hours apart (10:00 and 12:00). I filed a complaint the the FCC for both calls, of course. I don't understand why they can't trace it. This is ridiculous!