My Friend "/kill"ed me and i cant respawn

Note! I didnt know if i should post this here or on spigot So i tried here first

Hello! i tried searching for this issue but had no such luck! I got "/kill"ed by my friend and now i cant respawn! i tried restarting my game, Changing the version of my game, And restarting the server but i still cant respawn and because its my server I NEED ON THERE!!! So pllleaaase help me!!! Please i dont know what to do!

By the way its minecraft 1.8.8 but it wouldnt let me put it there

Thanks
-willy