It's a scam!! They pretend to be from the IRS and try to make you pay with Itunes vouchers, they don't even speak proper english.
Don't answer!!

Just received this phone call and freaked out for a while. They called me 4:50pm, but I saw that IRS close at 4:30pm. A guy with a british accent told me that I had to pay a bill of US$ 15.000,00 because of misunderstanding the taxes from 2009-2015. But I was never in the U.S. on this period, so it is weird that I had to pay for taxes if I was not leaving here.

I received a call from 212-436-1000. This person said he was Brain Hoff from the IRS. He gave me a case file number and a badge number. He claimed that the IRS had audited me from 2009 thru 2015 and that I owed $2400. He also read me several violations I has supposedly made with the IRS. I asked him to mail me something and he said they had and that is why he was calling me and that if I didn't pay the police would come to my house and arrest me within the hour. After I disconnected the call my phone rang from 911 saying I was running from the IRS. This is a total scam. Pretty scary they can call you from a 911 number.

This number is an actual IRS number on the gov.com domain. Not sure how the spoofed phone numbers but be weary of any calls from 212-436-1000.

Received a call at noon.   British accent keyed me to scam.  Hung up without talking to them.  Will see if they call again; if they do, the number will be blocked.