It's amazing the dumb people who "ask these scammers to be put on their do not call list" just telling them they will answer their phone when the scammer calls,lol,lol.
This company calls 2-3 times per day about knocking down our credit card interest rates. We've asked them to quit calling and they still won't stop. They are very rude and have hung up on us when we speak to a live person.
These crooks do not care for the DNC rules. As noted you should never respond to calls where you do not recognize the name or number . If you do they know they have a live person and will sell your number to other crook telemarketer who will try to rob you of your money and personal information.
My mother is in her 90s and these calls are confusing to her. I've added her to do-not-call lists and taken other steps to help her recognize unwanted calls on her phone. She has never had a credit card in her life. I wish someone would invent something to add to the phone that you could push a button and the caller's number would be locked or simply melt the phone.