DNC is only a deterrent to legitimate businesses. Since Scammers generally use 'spoofed' info n the CallerID it will have no effect on them and the feds are not even going to bother to chase them all down. There's just to many and as soon as most folks block them they just change to a new spoofed number.
Block them and ignore. You'll just frustrate yourself hoping DNCwill help or even respond.