That is a horrible thing to have to deal with. As a mother of a 10 yr old daughter myself it is the worst thing to see your little girl with a broken heart.
If you can speak to an attorney about this and he can give you advice on what you can do legally to see if you really have a leg to stand on. That would be a start , but attorney fees and court costs sure do add up. It may be better to cut your losses , return the horse and shop for a new equine buddy for your daughter....which will be hard for her at first I am sure.
This is an experience that I had a few summers ago: I was going to free lease a pony mare for my daughter for the summer who was ridden by beginners on trail rides ..etc. I went out and rode this mare who was a sweet heart for me and also rode her on a trail ride and she did wonderful as well. We made all the arrangements to have her at the barn that I board at. My daughter was 8 at the time and just loved that pony like most little girls. She spent a week getting to know her , brushing her , leading her etc...and then it was time to ride. She got on and this pony bucked her off! While she was not hurt (thank god!) The pony went back to her owners ! My daughter was heartbroken and cried the day the trailer came to pick the mare up.
It took many,many months of looking to find the right horse for her and then we found our Paint. We have now owned him for 2 yrs and is perfect for her and our family.
Trust me , I came through the free lease experience much , much wiser!
I know that isnt exactly the same situation that you are in but if you have to let this mare go, you will find the perfect horse for your daughter and she will have many, many new experiences/adventures to look forward to.
As far as the trainer goes.....Find a new trainer for your daughter. I agree she shouldn't be acting that way especially in front of one of her lesson kids. She sure isnt acting like an adult and she is supposed to be a role model for young riders?
Whatever you decide to do , I hope it all works out....keep us posted. It def. Isnt fun when we have to go through things like this!
Horses and children, I often think, have a lot of the good sense there is in the world.
Josephine Demott Robinson Feed, muck, groom, ride. Repeat daily!