May 12, 2017
Received this call from 646-367-4158, identifying as located in NY. Robotic message threatening legal action, as others mentioned above. Exact message: "Just to inform you that a lawsuit is being issued against you from IRS which is Internal Revenue Service and we are calling you to get your lawyer's information who will represent you in the courthouse. So kindly please give us a call back to resolve this issue as soon as possible. Our callback number is 646-367-4158. I repeat 646-367-4158. Please call us immediately or legal actions will be taken place against you. Thank you."
I called the number back and the call was immediately answered by someone who did not identify with his name, only "IRS", and spoke with a foreign accent. When I told him I received this call, he asked if I'd received a certified letter. When I said no, only the message, he asked if I received the message on the number I was calling from and he would look up my account. I said I didn't know which number had received the call as I have more than one and asked him to identify himself. He refused and I said I believe this is a scam and he said "well if you think it's a scam you can hang up now." So I did.
No records come up as associated with the IRS when I search this number via multiple search options. I declare shenanigans.