Just got a call from this number…  They left a message & it was the same ole credit card rate lowering thing I get a half a dozen times a week via robocall …  CID = "Cell Phone HI"…

I am on the Fed & my State Do Not Call Registries which are both absolutely worthless…  

Explain how you expect those registries to "work".
The Do Not Call registries are not call blockers.
The Federal and State Do Not Call registries work exactly as the lawmakers intended them to work.
They are lists of phone numbers, nothing more.
Legitimate telemarketing businesses use the lists to avoid calling people who do not want calls.
Charities, survey businesses, and politicians and political organizations are exempt from having to use the federal list, but must maintain an internal do-not-call list of their own.

Dishonest and stupid businesses do not use the registries, they have their own lists or simply program their autodialers to call all possible numbers, hoping a gullible person will answer.