How do i stop them from calling my dog by the wrong name?

hi i have a dog and his name is Romeo and he acts like it hes sweet and caring and he hardly ever is aggresive i was there when he was born and ive been with him ever since. Hes scrawny but VERY strong but he looks very weak. And my family besides me and my mom call him Rosko i asked them to stop then i tried to ignore it but they wont stop calling him Rosko and when they do call him Rosko he wont even pay attention to them. What can i do to stop them from calling him Rosko??