Call Blocking

Hello,
I set my call blocking to “Hi”; after being harassed, for the last several years, by “Windows support”. The name was “800 Service” in all past cases or “Dell Support”. I added “800 Support” to the name block; however, only a day later they snaked around the blocking method and again harassed me. They used number 8891 and name 8891. Since this is not a valid phone number is there any way to block these phony numbers?
Wish list:
I want legal remedy, military solution or better yet; a fool proof call blocking method.

I just use the info that is displayed as name and add it to call block. Seems to work for me whether it is a name or digits.