I just made a contact Called "Scammer" and add new numbers to that contact, I added a Duck Quacking Ring tone to it to make it funny. You can make a "silent ringtone" by recording a ringtone in a silent room and use it as a Ringtone, Don't forget to turn off the Vibrate for that contact too!
I did make a few Scam contacts and separate the Card Services from the Free Cruise, An another from Alarm company scams and Insurance scam.
One thing I did find out was that my calls dramatically reduced once I added a Not Tracking add on to my computer browsers. I used "Ghostery" and Adblock Plus. Seems they are using tracking cookies to make call targets.
Received a robo-call from "Rachel from Credit Card services". Pressed '1' but the line went dead. Those bozos have been calling me for over 3 years, off an on. I keep in my wallet a phony credit card details, and when they do answer I pretend to be interested and waste as much as I can from their time.
I was counting my blessings that these guys weren't calling me for a few weeks. That ended today. Even claimed to be affiliated with my bank, and said he could see my payment history. I asked where his office was if so, and the response was to ask the question if I wanted to talk to a "senior manager". I finally received the answer that he was in Jacksonville, Florida, but he wouldn't answer any further questions. Just as I knew, the line went dead before the "senior manager" came on.