Claiming to be IRS.  I am a CPA and the IRS would never call you to say they are filing a lawsuit against you. Give them no information, not even your name.  I called and messed with them - they are not from the U.S.

My caller id noted that the call was coming from 360-566-2212, but they wanted me to call 360-450-0205 because the IRS was suing me.  Thank you everyone for the warning to not bother calling back!

Received a call that the IRS had a claim against us. Told to call 360-450-0205. I knew this was a scam.

I received a call from 360-566-2212 to phone 360-450-0205 immediately as I was being sued by the IRS! Returned the call to 360-450-0205 but nobody answered.

My call blocker blocks all calls from this area code. That is hundreds of possible numbers.
Buy a call blocker for $49 on amazon or ebay.

google 'call blocker'. One ring and they are gone.
Caller ID service is required for blockers.

Learn to ignore bad phone numbers. Stop answering every call.
If nobody answered, and nobody called them back, the scammers would go out of business.