The best thing any receiver of these scam IRS calls can do is to contact the Federal Trade Commission at 877-FTC-HELP. They will provide you with a reference number to give them every time you call back with info on yet another IRS scam call. Yes, it's a bit of a pain, but every bit of info we can provide, i.e., the number they called from, what they say to you and anything in the background you may hear/observe helps the FTC to track and shut them down.