How did this scammer vet this orany phone number? If it is a debt collector does it mean they sold the phone number to the scammer or is it just away to get contact so they can try to collect on a debt that is not owed to them? This should be a federal crime.

Caller ID Spoofing:

https://en.wikipedia.org/wiki/Caller_ID_spoofing
https://consumercomplaints.fcc.gov/hc/en-us/a ... ID-and-Spoofing
https://www.fcc.gov/guides/caller-id-and-spoofing

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

Scam.  Do not acknowledge.

Who are these [***] artists with the foreign accent...have a good mind to turn them over to the NSA/FBI...if it was closer, I would drive over and have a few words with them!!! Annoyed in OC

Arrest warrant has been issued and under federal investigation to our address.