888-775-1591

It says it's from the IRS, and if I don't return the call, I will be arrested.

There is a fairly common IRS or "tax scam" being practiced by scammers in both Canada and the USA.
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.

Talked to someone named Sam he wanted 940.00 right then or we would have to go to court. Would not explain what mistake was made. Just said that we had been audited

Scam Scam Scam.  Don't respond and don't call back.  Just block 'em and ignore 'em.

My brother and his wife received similar phone call.  This guy told them he is from IRS and need to call him back right away.  I called the number for them after I did my research.  I called them back and told them the call was a scam and reported it to the local police.

I also received such a call and reported it to the IRS fraud division.  Hope they find this guy throw him in prison and throw away the key.