Want to eliminate robo/scammers/[***] calls?  Do the following if you have an iPhone.
1. Take each one of the people who call you the most and place them on your favorites list.
Do this by going to that person's contact phone number on your contacts list and scrolling down and depressing
the Add to Favorites.
2. Once all your contacts are on the contacts list, go to Settings on your iPhone and about the ninth item on the list
you will see Do Not Disturb.  Click on this and turn on the Manual and Repeated Calls features and WALLA, all
robo/scam/[***] callers that call you will automatically go to voice mail.
3. If you need to remove any contact from your favorites list, just depress Phone, Favorites and find the contact you
wish to remove and scroll to the left and delete it.
You will notice that every idiot that calls will soon determine that it's not worth their time to continue calling your number.  Please copy and paste this and pass it along.  You may be able to do this on your Android phones to.
It has worked for me and given me peace of mind in not getting calls at all hours of the day or night.