Received call from 414-551-1634 three times in one day. Phone call was muffled and difficult to understand.  Message left says, "You have IRS law suit regarding case file. Call 414-551-1634."

I looked up area code:
Wisconsin, Mikwaukee county ???

I think it could actually be a debt collection company's attempt to scare citizens into calling them back regarding THEIR debt collection paperwork.

But, they do have a different phone number on their "demand for payment" paperwork.

Clever and deceitful.