Yes, they do need the DNC llst if they are a telemarketer as per the definition of a telemarketer. They need to scrum their lists. No, they don't buy the list to have "good" phone numbers. That is simply some fantasy someone made up (probably a telemarketer). It doesn't matter where they get your number, the law is the law and real legitimate companies abide by it. Crooks and criminals never do.
Also file a complaint with your State Attorney General's office.
List of State AG’s offices: http://800notes.com/faq/attorney-general
Use this web site to find an attorney in your state that will probably take the case on a contingency basis (no money out of your pocket up front): http://www.consumeradvocates.org/
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
https://www.merriam-webster.com/dictionary/telemarketing
telemarketing
play
noun tele·mar·ket·ing \ˌte-lə-ˈmär-kə-tiŋ\
Definition of telemarketing
1. : the marketing of goods or services by telephone
telemarketer
play \-tər\ noun
You have the right intentions but this doesn't work because the gov doesn't pay attention to these goons. Even though the NSA has the ability to trace these calls, (and probably bomb them where they sit), they can't be bothered. They are looking for more nefarious criminals. Best solution is to not pick up. If they keep calling, block their number. This can be done online.
"She said God I won't remove your number blah, blah blah. And hung up on me!"
Ask your cell phone provider how to block the number. Some will let you do this online, others in the store. Keep doing it until the POS's of sh!!t stop bothering you.