A.) Seek someone’s supervisor to appeal their decision. If you are unhappy with a bureaucrat’s  or a shop keeper’s decision, you would ask to speak to their boss in order to get a different decision. “When the store clerk said they could not refund my purchase, I went over her  head and asked to speak to the owner.”

B.) To go over one’s head may also mean it is not understood by a simpleton. “When I explained that energy ius equal to mass times the speed of light squared, well, it just went over his head as  he doesn’t understand science.”