Other IRS scam tricks:
Contacting you by email. The IRS does not do this.
Sometimes the scam works by saying you will go to jail, revoke your license, any excuse they can think of. They sometimes hand up and call back actiing like they are the police department in your area etc. Dont believe any of that garbage as no one does this on the phone like that, and certainly not the I.R.S.
They may know your last 4 digits of social security number, dont trust what they tell you.
Scammers fake the IRS toll free number so your caller ID looks real.