I received the same message today, the 11th of July 2015. As a tax preparer, please do NOT fall for this scam. This is NOT how the IRS would inform people if they are being audited. The IRS will send a letter, not a threatening phone call.
I got this call- the best thing to do is *67 your phone number and call them back and harass the crap out of them. I do it on a regular basis and the guy is so mad at me he apologized. I will not stop calling them and harassing them as long as they call me.