Yeah, see, the IRS does NOT file a lawsuit until after they have contacted you multiple times via US Mail. And I'm sure that they identify themselves as the IRS on the phone. And if you live in Arizona, they don't call from Wisconsin. Nor do they call on Veteran's Day (as they did me), when most gov't offices are CLOSED.

One problem with your post-the IRS does not call AT ALL. If the IRS has ANY business with you, it comes in the MAIL-usually something you have to SIGN for

I get the same call and same voice message, "we are calling regarding a complaint we received. If we do not hear back from you, we will submit your file for further review". Seems like a scam, I'm blocking the number.

A complaint regarding National Payday Loan was filed against me and they want their money because the limitations are about to run out.  Never had a payday loan SCAM!!!

Report them:
https://www.treasury.gov/tigta/contact_report_scam.shtml