:( don't envy you there. :roll: It annoys me how some parents just go buy horses/ponies without fully looking into their background, nature, health etc.... Afterall, it is classed as a dangerous sport and the safety of their daughter should be of upmost importance!
Has Gypsy had her back, teeth etc checked? Not saying its any of those, but might be worthwhile ruling them out.
I know it might not be your place, but have you tried talking/explaining to the parents? Try to get them on board and back you in the way you are trying to help.
I think its very heart warming, you offering your time to help, and they should be helpful and grateful in return.
Sorry had to get that off my chest.