vampyregirl, I so heavily sympathize with you. It seems in UHC or Team Skywars that TONS of people literally just want to watch the world burn. It's sad and really frustrating, especially for the normal people like yourself who just want to play.
We're working on a plugin that will prevent team killing and hopefully will, in the future, completely remove the ability for trolls to kill their teammates. As
@Guardi4n said, please record or even take screenshots of people team killing and we will deal with them post haste.
Thank you very much for your concern. My deepest apologies that some of our players don't understand teamwork. The problem will be dealt with swiftly and effectively.