I helped sell a registered QH with impeccable breeding for a friend years ago. She was sold as a broodmare ONLY, no riding, with a foal by her side and bred back. Broodmare only,NO riding period. The mare had thrown previous babies that were sweet, and trainable for anything.
Anyway, she was sold with a written signed contract about being unridable and a broodmare only. The new buyer knew and signed the contract, was told by me and the seller numerous times about not riding, broodmare only.
New owner bought the 3 in one package for a great price. Was happy as a clam that the mare was so docile and sweet, her babies were sweet and loving and gentle and easy to train.
Guess what? The new owner decided that there must be some mistake, that surely this mare could be ridden, that the seller was just being silly. Well, she saddled up this mare and promptly got thrown, bad enough for a concussion, ear damage and some vision damage, plus broken arm. She tried to sue the seller. Basically the judge threw her out of court, she had a signed written contract stating the horse was a broodmare only, so when she decided to ride the mare, she was taking her own chances and therefore seller was not liable.
In this case with the OP, when a seller(and everyone else on this forum) honestly tries to tell a buyer the horse is not a good match for whatever reason, or tells someone "broodmare" only, then I think the OP is out of luck. She figured she knew better than the seller about the horse and lost.