For anybody on an android phone,I highly recommend https://github.com/aj3423/SpamBlocker
It is highly configurable with every feature I've ever wanted but could never find for call filtering in the the app store. I've essentially set mine so that if the calling number is not in my contacts, or is not a number I've called in the last 90 days, the phone never runs and the call is sent to voice mail. But it supports lots of other mechanisms to filter with like regex, or how many times the number has called within a given timeframe.