Even if you have your phone registered on the do not call registry, the only thing it cuts down are the actual telemarketers. Scammers are using voice over IP, or hacking and using random phones.
I've gotten three separate calls from card holder services in the same day. One was local, two were from other states. Calling the number back usually results in a recording saying the phone number is disconnected. Occasionally I get a live person wondering why I called them. I'll then explain to them about getting a robo call or scam call from there number. And send them a screen shot of my call log as proof.
Had a scam call from Microsoft tech support a while back. Work phone showed a number originating
From Ohio. Several hours later, they called my personal phone and it showed that the call came from China. They left a voice mail

Got to looking at the rest of the numbers and realized that it was the same number that called my work phone earlier in the day.