I was called from Montana number 406-941-1686.  Was called by this number stating it was my last chance because I was being sued by the irs and to call back immediately.  It was a robo message. I did call and a man with strong foreign accent answers.  He immediately asked for my name, I said shouldn't I receive mail from irs about this first and he again asking for my name again so I hung up.  I checked and found out about big scam with calls from Montana demanding payment or you would be sued.  According to irs, they are phishing calls and irs would never ask for info over phone.  Three would also am mail to contract

A message from this number staing they were from the irs and are preparing to sue. I called back and it was a continued busy signal. I know that this was not the U.S. IRS because they don't do business over the phone. They will make contact through the mail. I think this is a scam of some sort or a credit collector of some sort.

IRS Scam:

The IRS does not need to sue anyone.  They send you first class letters delivered by the Post Office.  Several of them.  Ignore those, and they then send certified letters that you need to sign for.  Again delivered by the Post Office.  Ignore those and they simply freeze your bank accounts and anything else you own.  If they can do that, then why would they bother with a court case that might take them years before they get in front of a judge?  They also do not bother arresting people for a few thousand dollars for the same reasons I have already given.

Official IRS Government site detailing this scam and providing links to report it:
http://www.irs.gov/uac/Newsroom/IRS-Warns-of-Pervasive-Telephone-Scam
https://www.irs.gov/uac/Online-Scams-that-Impersonate-the-IRS
https://www.irs.gov/uac/Tax-Scams-Consumer-Alerts
https://www.irs.gov/uac/Newsroom/Phone-Scams- ... 6-Filing-Season
https://www.irs.gov/uac/Newsroom/IRS-Complete ... -Scams-for-2015