addendum: Decided to call the number to see who answered. Just heard repeated busy signal. Probably one of those robo-dialers that calls thousand of numbers and then sells the ones that got a human answer to a telemarketing clearing house.
I had placed my home number & all of our celphone numbers on the National Do Not Call Registry (https://www.donotcall.gov/) 4 years ago, but since then had changed service providers twice. In the small print it says you may have to resubmit your number if you change providers ...which makes ZERO sense to me as it's the same number(have had it for 20years!). So resubmitted my number on list. Says they have 30 days to stop calling. We'll see :x