I got the same call. I guess I missed it because it came in September and I caught it while going through old voicemails. I knew it was total BS but I called back anyway just to see what they'd say. I got a voicemail asking me my situation so I could be moved to the top of the priority list. I hadn't even finished listening to his message before he called back. I told him I had received a message about a "Federal Investigation" and he told me he was sorry and that it was a mistake. I hope people don't actually fall for this stuff.
Same IRS call as everyone else has reported from person with broken English. I love how at the end of the message he said "have a blessed day." That made me laugh at least...
I'm being arrested this afternoon for tax evasion and I'm supposed to call back as soon as possible so I can get the details of my arrest. He did tell me to have a blessed day, so that was nice.