Signature proof of divorce papers served

If one of the people in the divorce action will not sign for certified mail, or answer the door when the Sheriff comes to serve the papers, what is the next step? This seems like it can go on forever. Im ready to move on and getting depressed over this situation. Does North Carolina not have a Law in place for this? Some people just like to make you miserable since their lives are miserable all the time. Please help with this questions…please