KitPvP With kits

Hey, ive made a kitpvp plugin with kit. You can do /kits to select a kit. The donators can do /donatorkit. if you Die you will get 2 nether stars for the kits so you don't need to do the command. Ive made a system that if you select a kit you can't select a another kit and it will give a message than. you need to die to select a another kit.