[ProtectOurFreedom]

I use NoMoRobo — it is quite effective at blocking the crap. If you want to help, you submit numbers that did get through so others won’t get hit by them. Helping is optional, but I like doing it.

[Buckeye McFrog]

I use NoMoRobo — it is quite effective at blocking the crap.

An air horn by the phone works well too.

[KeyLargo]

The Do Not Call Registry is somewhat useful but not very effective at preventing these types of telephone scam calls.

https://www.donotcall.gov/

I purchased a Panasonic phone which I can block any such phone numbers myself.

https://www.google.com/webhp?hl=en#q=telephone+phone+call+blocker+reviews&hl=en&tbm=shop

https://consumerist.com/2015/07/28/consumers-put-robocall-blocking-devices-to-the-test/