Rob call from irs. Calling to mess with them and have a ton of fun

I received an email stating IRS had began moving forward with criminal charges if i did not get this resolved.. the number they provided was 1 (646) 809-9729 I tried calling them several times but got a busy tone so i started to wonder.. starting looking into it a lil further and looked up the number and everyone seems to have got the same outcome Fraud !!