866-269-9863

Caller I.D. said "UNAVAILABLE."  I do not answer anonymous phone calls or calls that only give a city name as the origin.  'Nuff said.

My CID said "800 service". Same here I do not answer unknown numbers and if they do not leave a message I just block them. They only let the phone ring three times and hung up before my answer machine picked up. With so many scam and robo calls who bothers anymore to answer their phones when its someone you do not know.  If you don't leave a message I will never contact you back and I just block all numbers that do not leave message. I do not sit by my phone that I can pick it up with only three rings.

Left no message and ID "Unavailable" so I blocked them.

Left no message ID 800 Service

See if your local phone provider offers *77. It will block all calls that caller ID is Private, Blocked, Unavailable, Out of Area, and Anonymous. https://en.wikipedia.org/wiki/Anonymous_call_rejection