So you don't actually know if it was a DNC violation now do you?  Do you even have a clue what the DNC is, what it does or doesn't do, and what it can and can't do?  Probably not since you never read the following (note that it covers sales calls and nothing else):

What the Do Not Call lists covers and doesn’t cover and why:  https://www.consumer.ftc.gov/articles/0108-national-do-not-call-registry