Robocalls

You may want to check out this link on blocking anonymous calls.

The OP isn't receiving anonymous calls.  If OP is reporting the Caller ID data to Nomorobo, it's obviously not anonymous.  Moreover, Anonymous Call Rejection only works if the Caller ID reads "Private" or there is no Caller ID data.

I think your Anonymous Call Rejection has run its course because...and I can't speak for everyone...I haven't received a private or anonymous call in over 3 years.

The calls aren't anonymous in the strict sense of the word.   There's either a fake, unverified caller-ID name or a geographic location (e.g., "PROVIDENCE RI").   As they used to say in the TV commercials, "We can land a man on the moon but..."

I can't believe there's no technology solution to this. 

I don't know if Cox is still implementing STIR/SHAKEN (verified calls) because I've recently received some legitimate, familiar calls and there was no "V" in front of the numbers. One call was from our Management Office with a Verizon landline-telephone number...no "V."

I also checked my Cox Call History for the past 120 days, and none of the logged calls had a "V."  I've received V-calls before but nothing in the past 4 months.

I just noticed that myself.  The last call I got with a V verification was on 10/17.  Nothing since then and I actually do get a valid phone call once in a while😀. 

I think the last one I got was last year.  I got a call from an un-V'd number and then the number called back with "V."  I don't trust STIR/SHAKEN.

The North American Numbering Plan Administrator (NANPA) amasses a list of assigned numbers from the providers twice-a-year and submits biannual reports to the FCC as the Numbering Resource Utilization Forecasting (NRUF).

Due to the sensitivity of this report, the FCC would never release or allow anybody to access it.  However, with your suggestion, I suppose Cox could send a caller's number to the "database" and receive an "in-service" or "not in-service" response.

However, as you noted, scammers are spoofing in-service numbers, so the reply from the "database" would be "in-service" and then allowed.

You cannot rely on a company or agency to police your calls.  The gov't has been failing for 20 years, and Cox does not want to get into the business of deciding which calls to block.  The only foolproof way is to install a call-blocker and maintain it with an Allow Only list of numbers.

I never heard of a call blocker but just found call-blocking phones on amazon.com.   Time to check these out.   Tonight I got a robocall at 8:15.  It's getting out of hand.

Call-blocking telephones don't won't work well with onetime-use numbers.

Scammers will use a legitimate (assigned) telephone number, war-dial hundreds of people and then move on to another legitimate number.  By the time you get around to blocking this legitimate number, the scammer would have already moved on to another number.  You'd just be blocking a ghost.

Call-blocking telephones do work well with the numbers persistently calling you as well as "Private" and "Unknown" calls.