If your phone supports it, Nomorobo. For smartphone I use Mr.Number & Blacklist which helps get rid of BS texts.
Why would I want to tie up my phone with a script? That's how it works, right?
For the land line I use a combination of Nomorobo and a netbook that's on 24/7 running PhoneTray.
I have absolute power.

Just like many hoster services are competently blocked from my website's. Steadfast, Digital Ocean, OVH, Amazon AWS? All get the nice 403.