I'm on the do-not-call list and I've only gotten one telemarketing call in the last year; but I'm still inundated with calls from outfits I've never heard of that are or claim to be surveys or charities. They're just as noxious. And then there's the political campaign commercials.
The one telemarketing call sounded like a criminal enterprise phishing for banking information. The local sheriff's office agreed that's probably what it was but said there's nothing that can be done beyond hanging up on them, since most of these guys are offshore and beyond the reach of American law.
Because of the "surveys" and donation requests, I signed up for
Verizon Iobi. Once the marketers call, their number can be blocked.