IRS scam, threatening a lawsuit, heavy Indian accent, same phone call several times now from 952-314-1908

Just got the same call. I did not answer but I tried to call back and no ring. Says it was a final notice from the IRS and that they've been trying to reach me via mail. I did not receive any letters

I received a robo call telling me there's a lawsuit from IRS against me and I should call this number.  So I did, and the man with heavy accent gave me his "employee ID" and "case #", told me that the call is being recorded by federal gov't, and that I owe over 8K.  So, I supposedly have a choice between paying now the way he would instruct me, or to immediately (in a few houra) hire a criminal attorney and fight it, otherwise I would get arrested and my bank account go frozen.