a) Kudos for getting out and giving back. You took your strength and utilized it ten-fold. That's really cool.
b) Had this done twice, once with my just-desserts and once with my face on the concrete.
c) Idk if a lot of the people who were volunteering were in the same space as you but some people are just warped either by life or by the situation and it sounds like you found a real rotten one. Worst part is she's still probably out there doing it to someone else. I think it's kinda like when they say stuff like how you can't become rich without stepping on others. It takes some really skeezy characteristics to get ahead in this world, and they all seem to be the exact opposite morals promote.
Fuck that woman though, you did what you wanted to out of the good of your heart and your program could have made a big difference. Hopefully now there's another program that has floated to the surface that has taken its place and does okay. I wish you had a heart to heart with the director, but I bet you ten bucks you ended up leaving if one of the people who turned on you was her. All things aside, I'm sorry you had this happen to you. It's outright rotten.