I just had the same message that I am being sued, but they did not give the name of the person they are calling. I called the number and of course no one answered. If it was the IRS then there would have been a message of the hours to call.
I just got one of these voice message to call the 360-285-3577 but their name was cut off at the beginning of the message. All I heard on the message was, "for information about this case file call the 360-285-3577". So I called it to see how they answered the call, the women who answered the phone on the first ring said, IRS how can I help you? Well, I almost laughed in her face before I hung up the call. I have had to call the REAL IRS many times but they NEVER answer the phone. It is always automated until you can get a live operator.