I can only imagine your pain over this! While I know this is easy to say, but so very hard to do - consider it their loss!
They're cowards and, unfortunately, were never really your friends. But guess what? That type of person really has no friends - they always have to find a new target for their mean streaks. Wonder who their next target is?
I'm glad you had the courage to tell them the truth and that you also have the courage to return to the camp to face them down. Clearly they don't have the guts to face you or apologize for their meanness. Guess they're stuck in 7th grade mode.
As for what to do - you don't have to do anything as you did not offend them. Carry on with your life, find real friends and leave them behind. That's where they belong.