Called yesterday at 8am, and today at 11:40am. Did not leave a message either time. Another website indicates it's a spam/hoax caller who claims the IRS is filing a lawsuit. Sounds like a scam to me. I've now blocked their number.

I keep receiving calls from this number, but they never leave a message.  When I pick up the call, there is a big delay before anyone comes on the line.  Therefore at that point, I just hang up.