This is the mother of scams. Uses the irs story to scare victims. They run a very sofisticated scamming tactics. This telephone number can't even be blocked. call your provider to block it.
I received the same voicemail message stating that they are the IRS. I called the # back and it rang once and hung up. So I called again and spoke to a man with a strong foreign accent. He immediately started asking me for personal information and I called his bluff and told him he was a scam and that I was reporting him. He actually told me to F*** off, so I know he is NOT part of the IRS. I am reporting this number to the IRS today.
I called it back and no one answered, so I look on here and found all your helpful comments. Well it is the holiday of giving, who ever it was is trying to make a few dollars. LOL My advise: get a real job