I get calls from them EVERYDAY, on weekends, weekday, does not matter, sometimes 3 - 4 times a day. I have told them to STOP calling, but they won't. I haven't even answered it in months ...
In android, you can assign this number to a contact.
THEN
Edit the contact and you'll see a 'do not ring' setting.
Assign this and presto, no more hassle.
I bundle all these numbers into a single contact named "Blocked"; and presto magiko all better!