fraudulent request for money and SS #

Received repeated calls telling me that 2 warrants will be served against me because they detected fraudulent activity on my social security number. they said I would be served these warrants at my home or place of employment unless I call them, with the case number they provided, to straighten this out. If I was served first, I would lose my right to appeal. What kind of scam is this? How stupid do they think people are?