Ah yes, yet another scam call informing me that I'm am the subject of a federal lawsuit. Really? Don't they know that all this legal crap has to be sent by mail?

Criminals do not care about what is/isn't legal. They are on a mission to extort money any which way they can. Use the information below to report them to the appropriate entity:

There are numerous telephone and email scams in which individuals claim to be employees of the Treasury Department. These scammers often state that they are from the “Department of Legal Affairs,” offer grant money in exchange for you wiring a small payment, or threaten to arrest you within a short period of time unless payment is made. Do not provide personal information or payment to these individuals.  Their actions are crimes under Titles 18 and 31 of the United States Code, and the Treasury Office of Inspector General is working to stop them.

If they claim to be from Treasury, report  it to OIGCounsel@oig.treas.gov with a description.  If it was a phone contact, include:
the exact date and time that you received the call(s)
the phone number of the caller
the geographic location and time zone where you received the call
a description of the communication.

If they claim to be from the Internal Revenue Service (IRS) or it is about taxes, report it to the Treasury Inspector General for Tax Administration at:
https://www.treasury.gov/tigta/contact_report_scam.shtml

https://www.treasury.gov/services/report-fwa/Pages/Report-Email-Scams.aspx

Got a call saying federal investigation I am the subject of lawsuit. I told caller I am busy catching Pikachu now call me back 5 mins. than she hand-up! LOL. Anyway, how to stop this type scammer call? I block ton of numbers from my device but they keep switching. I have at least 5-6 calls a month avg, some time they left a voice message, so annoying...