There is a fairly common IRS or "tax scam" being practiced by scammers on both Canadian and USA residents.
USA tax payers should read this:
http://www.irs.gov/uac/Newsroom/IRS-Reiterate ... -Telephone-Scam
Short answer:
The IRS never initiates a contact via phone.
They always send a snailmail first.
Oh No I am in trouble from an unidentified caller, serious consequences....my home and my employer,,,foreign accent agent who's name I could not understand...these scum sucking scammers try to intimidate us . Ignore them, all they want is to steal money from unwary citizens of the US. This is the second time I have been contacted by these bottom feeders.