You can go into your cell phone settings and set the "do not disturb" time from 12:00 AM to 11:59 PM and only calls from people in your call register/phone book will ring thru to you. All else goes directly to VM. My cell phone rings are now from the people I know.................ONLY!
I did this to my iPhone and the wife's iPhone and now my cell phone only rings when it is someone I MIGHT (emphasize know them) to. Most BS calls don't even leave a VM.
This is a FREE thing already in your phone. You do NOT need to pay a fee for an app that blocks calls!!!!!!!
This is really handy during this vicious political season!