Three calls from this number today. The first was an automated message that the IRS has filed a lawsuit against me and I need to call them back. Whole bunch of signs this is NOT legit. I live in Florida and this is a Seattle number. The message never addresses me by name or other personally identifiable information, just "you." And quite simply the irs just does not handle back tax or underpaid tax situations like this. I reported the number through the irs website instead, with low expectations.
I didn't answer the phone last two times thank God for caller ID, but at this point it's slowly turning into harassment.