Same did I! received a phone call saying that IRS had a case opened upon me! I got scared as i am not even US citizen and now being in US for a temporary assignment... i called back the number and a indian accent "IRS agent" said that i had to pay 7334 dollars otherwise he was going to issue an arrest order on me! I was very scared actually... but then i told them that i was not going to pay anything and that i needed to talk to somebody... they told me that if i closed the call the order of arrest was going to be issued immediately! I closed anyway. The strange thing is that they knew my home address in the US and my email address! they f...up my day today!
I have 2 different bogus numbers calling me now with this scam. Be sure to report it to the IRS and/or the US Treasury whichever they say they are at the time. These are known scams if you look on the governement websites. The IRS would never demand money over the phone and threaten arrest within 45 minutes if they do not get it - or whatever people say these scammers are saying. Just hang up and block the number but do report it to the government.