Also, if you hear: “This is the IRS” :)
I'd give him my name (maybe Sherman T Potter or Nigel Tufnell or someone from Monty Python) and my address (either 1060 W. Addison in Chicago or 1313 Mockingbird Lane) and so on and so forth with lots of "I'm sorry can you say that again?"
There are YouTube channels featuring "scam the scammer" calls that go on for a LONG time. They're comedy gold. And justice in action.
My grandad had a ball with those people; when the called said IRS (Eye-R-Es) - he’d respond with “Iris? Ain’t no Iris here” and it went on from that. Hilarious.
Lately the ones I get from the IRS say they are “a law enforcement agency with the IRS”. It’s all computer generated voice and so fake it’s pathetic that they could fool anyone.