I just got this same call. It's bs. IRS doesn't operate this way. It's like those phishing emails hoping to sucker in someone who doesn't know any better and getting them to deliver money via wire transfer.
Received call from this number on Jan 21 @ 2:26pm PST. Was not able to answer, VM claimed to be IRS suing me. I work for a law firm that does collections, so I know its utter male bovine digestive end product. If the IRS needs to notify you of something they do it by mail, as required by law.
This is FAKE. They actually called the TV personality, Dave Holmes, and he really messed with them. Enjoy: https://twitter.com/DaveHolmes?ref_src=twsrc%5Etfw