The problem is, and Hillary's Ace-In-The-Hole --- her Secret Service protection detail. They won't let anyone near her and she knows it. In effect she's immune from personally being served with a summons. Odds are oh ... 1000-1 that's why her lawyers refused to accept it.
Even the SS cannot interfere with matters of the court. Besides, she presents PLENTY of opportunities to be served as she goes out glad handing the peasants. Simply put it in her hand when she reaches for a handshake and say, “You have been served”. With cameras rolling to record it, of course.