I too, have purchased many with wonderful results and have been very happy.... but did purchase one earlier this year from Wyoming that was advertised as a bred mare- four years old, was to be her first foal. The mare arrived extremely fat, and also came in season after she got here. Had her tested by the vet, she was not in foal, had never been, and has a serious thyroid imbalance. She will not carry a foal unless on meds, and even then there is no guarantee at all. The mare was advertised as a broodmare. It didnt disappoint me so much that she was not pregnant- I have two stallions to breed her to, but the mare was expected, and the ad implied that she was at least breedable.
When I emailed the seller and her 'agent' to let them know, the seller said she would buy her back. This was last April. May came and went, then June. In mid June I finally got tired of the runaround, since I had been flat out told TWICE she would buy her back, and even asked for the info as to where and how to send the refund. Nothing came. When I finally put my foot down, after two months of feeble excuses, and told them to take care of it, they decided to change the rules and then told me no refund unless I played by the 'new rules'.
I did file a complaint here with MaryLou since the horse was sold through an ad run on the Sales Board, and MaryLou did investigate. She went out of her way to help me, however the seller and her agent just told more lies, and have never sent a refund, nor will they answer any email, except to reply the last time with nasty remarks, insults and insinuations from the agent. I had the documentation to back up the facts- and this is important! They are both banned from the Board and the horse is still sitting here.
I have thought of hiring an attorney, since I have all the documentation and then some, but if I do that, it is going to be for more than just the repurchase price of the mare at this point. I have filed many other complaints as well, through other avenues but dont know who/what your situation might be to do that.