won't stop calling

My phone number is unlisted, I signed up for the "Do Not Call" registry. Why is this person calling me???

Answer the phone and find out.   The Do not call registry does not screen,  monitor,  or block calls for anyone.   It is just a "List" of numbers,  maintained by the FTC,   that is required to be purchased by legitimate and registered with the FTC Telemarketing businesses.  Nothing else.   Any Telephone in the world can dial your telephone number regardless of any list and whether it is unlisted or not.

Don't answer harassing calls and engage in conversation. Most of these calls are fishing expeditions of one kind or another.  Read the articles posted on this site and take the time to research and stop the calls. They are not legitimate when they violate laws that are against what they are doing, even if you are guilty of the unpardonable sin of owing money they must follow legal procedure to collect.