I get a few calls like this every year. Thry claim to be the IRS &; it's a warning that they are suing me. Last time a man with an accent I couldn't understand called. This time it sounded like,a recording.
I received a robocall from this number today claiming that the IRS had filed a lawsuit against me and for me to call back (not going to happen) to make payment. Totally B.S. as the IRS would NEVER call using a robot, nor would they use a phone number out of the Seattle area. Generally, they will send a certified letter with all of the information regarding any debt, but they will not call you out of the blue, ever.
These people call all hours of the day and night and leave a message claiming to be the IRS and to call the number back. I did to tell them to stop calling me as I'm not an idiot and not going to give them anything. The guy cussed me out and threatened to come to my home and rape me and my daughter. Reporting to everyone I can find.