i just had the EXACT same thing happen to me at work. Only it was to the work phone and at first he couldnt pull my name up then all the sudden he did a background check with only my first and last name. It did scare me but im glad i thought it was a scam to start with so he got no info from me besides i would call him back in 2 hours if i cold come up with the $8000 he said i owed the irs or i would have to hire the best attorney in my town to fight the charges.

robo call stating a lawsuit with the Treasury Dept. I must call immediately to avoid being arrested or severe implications with follow.

Called saying I did not report all income for 2012- 2013 FY. When I said that wasn't true, he asked if I wanted the police to come to my door an arrest me. I said that's fine, just make sure they bring the proper documentation. He hung up, lol

Same scam from this 2098908430 number.
Kinda middle east accent,  told me that i was going to jail for 6 month for not paying my taxes from 2010. I reported this to my legal officer.

says they have received legal notice of a filing against me