It does no good to block as they just call using the next higher digit... 4721,4722,4723,4724, etc. you will run out of available blocking spaces on your phone before they run out of unlimited numbers. I have found a fool proff way to stop the auto dialer they use to harass people
called my cell. Caller ID said Ashley, IL. RoboCall - "drop whatever you're doing and pay attention to this urgent message. In just a moment I will connect you with a link to put $10,000 in your pocket." Totally bogus. Hung up. Blocked number.