How to stop scam telemarketers?

I am constantly getting phone calls from scammers. They are either for credit card debt (which I don't even have a credit card), or the more annoying one, my car warranty being up. I have tried putting my number on the do not call list and it doesn't work. I have went through to a person and told them to put me on the do not call list and it doesn't work. Today, I even played a long. When I got to the person, the first thing they said was "what year is your car". No good morning or anything. So I told them a fake year, to see what they would say, and they just hung up. I tried calling back and it doesn't go through. What do I do to stop it?