The U.S. Treasury would really like to catch these folks and put them out of business. If you received scam IRS or US Treasury Department phone calls, please report them to the Treasury Department's Inspector General for Tax Authority Office at the following:
U.S. Treasury Inspector General for Tax Administration (TIGTA). When that screen opens, there wil be a button/link on the right side of your screen labeled "IRS Impersonation Scam Reporting". Click on that link and fill out the form they provide. Unless we help, we can never stop these folks so please report your IRS Tax Scam phone calls to the US Treasury Department.