The DNC does a lot of good, with legitimate companies, but it's not a call blocker so it can't keep scammers from calling you. Only you can do that. Invest in a real call blocker or at the very least, don't answer calls from numbers you don't recognize and don't call numbers back "just to find out who called."
PLEASE tell me you're joking about giving them your CC info & SSN! If not, CANCEL those credit cards immediately and put a watch on your SSN.
NEVER give anyone who calls you this kind of information. You're just begging to be ripped off and maybe even have your identity stolen.