You can also file a complaint with the Federal Trade Commission at www.FTC.gov. Add “IRS Telephone Scam" to the comments in your complaint.
https://www.ftccomplaintassistant.gov/
Don’t Fall for New Tax Scam Tricks by IRS Posers
http://www.irs.gov/uac/Dont-Fall-for-New-Tax-Scam-Tricks-by-IRS-Posers
IRS Summertime Tax Tip 2015-18, August 12, 2015
You can also file a complaint with the Federal Trade Commission at www.FTC.gov. Add “IRS Telephone Scam" to the comments in your complaint.
https://www.ftccomplaintassistant.gov/
Don’t Fall for New Tax Scam Tricks by IRS Posers
http://www.irs.gov/uac/Dont-Fall-for-New-Tax-Scam-Tricks-by-IRS-Posers
IRS Summertime Tax Tip 2015-18, August 12, 2015