Have you talked to anybody who organized the VBS about your experience? I’m sure they don’t want their volunteers to have such bad experiences. I’d consider sending them an email outlining your experience and just letting them know that it was really uncomfortable for you and they may want to consider ways to help volunteers with all sorts of disabilities in the future to not have the same thing happen. My husband and I have done some nursery and Sunday School volunteering. Most kids seem, because of TV shows and movies, to understand disability at a very basic level. So he’s found that just explaining it that way—just like some people have a hard time hearing or walking, he has a hard time talking sometimes—helps them to understand that he’s not being funny or weird. Sorry you had such a bad time of it.