Everyday I get made fun of for my stutter

Everyday I get made fun of for my stutter Everyday if I even make the smallest stutter, a group of 3-4 people always do the mocking thing where they exaggerate your stutter. If this happened once or twice I wouldn’t care but now it happens every day and I don’t know what to do. I can’t think of anything to say back to them and at this point I don’t know what to do.