It doesn't help when the frauds, scammers and extortionist don't obey the laws to start with! And of course, it helps if you also file reports as well for those calls.
What did this caller do that violated the Do Not Call law? Polls, surveys, political calls and non-profits are exempt. Only calls that try to sell you a product or service are covered. If they called and left no message they didn't violate the law.