Most of the scam phone calls when I eventually manage to get the number which has called back, (scammers usually hang up on me pretty quickly as I'm a bit deaf and they've only got so much time to fleece people) are numbers that originated with a Travelsim number. Occasionally it's a number from another carrier, possibly spoofed.

Just check and reply to the various reverse number who called me register, most people will check that - so you have a good platform to belly ache about it there, and who your carrier is ...