VoIP Phishing operation where call blocking fails due to ever-changing #s.

What mobile carrier do you use? Some are more successful than others when it comes to spam blocking. There may be internal settings or third party tools available in the Apple & Google Play Stores that can help with blocking calls from unknown numbers, but it's a risky filter that rejects some good calls along with mostly bad.
DNC lists won't matter to them until they get caught.