Energy company scam. Just block the number if you can. Called twice today, second time left a message, so I know it's another one of these robo-call nonsense things. Something about "government assistance". Clearly a scam.
There is nothing legitimate about any of these energy scams. They (you) are already in violation of DNCL. What they (you) deserve is a formal complaint and a loud whistle in your useless ears. You actually deserve much worse than that, but let's keep this site "family friendly".
If they're robocalling cell phones they're breaking the law right out of the gate, doubly so if they're calling numbers on the DNC list. Your "marketing tactic" is blatantly illegal and your comment that if people don't like it they can ask to be put on their DNC list "simple as that" misses the point. People shouldn't have to ask favors of criminals to get them to stop breaking the law in the first place. If your company is doing the same, I hope the law catches up to you.