Recorded voice message claiming to be the IRS filing a lawsuit against you. They do not say your name, which means that it is not really the IRS, because the IRS would absolutely know who they are calling and address them by name. This is most definitely a scam, do not call them back!!!
They have called me several times. First time, it was a woman's voice (said her name was Mary Brown from the Internal Revenue Service) and a pre-recorded message threatening to file legal action. Today they called again, was a mail voice and this time they said it was the final notice. Good, so don't call me again. Funny, they never seem to know who they are calling. They are just phone phishing for a victim. It's a scam.
I have received FOUR calls from them within 5 hours!! I keep calling them back from my work phone, but it just keeps ringing and ringing. Too bad, I really want to B*tch them out!