You made a good observation about duplicate phone numbers.
I'm trying to collate so as to make it obvious that scammers are repeat offenders.
They recycle their toll-free numbers through several hosts / domains, since they're environmentally conscious.
On another subject, someone recently commented their views after a scammer interview.
I happen to experience first-hand, my friend receiving a cold-call that he's entitled to receive a $300 refund since "Microsoft is closing their Windows operations"
My friend angrily asked "Are you in the business of scamming?"
The reply ... "No Sir, we're in the business of philanthropy"
Philanthropy seems to be a booming business, there always seem to be far too may "free" offers than are takers!☺
A couple of presently active Popups: (2018 July 12)