The scammers actually call directly off the do not call list. The list tells them that these are active numbers. They wont remove you when you ask because they sell these list to other scammers.
The DNC list is pointless and counter productive. The only thing that will put a stop to this is to track down and prosecute the offenders and to stop allowing just anyone to spoof their phone numbers. This wont happen as long as the phone companies can make a profit from it. All we can do for now is to keep blocking the numbers and complain to our elected reps.