Selling sick horse

Hi there. I bought a horse from a horse dealer in Bloemfontein. I have asked for a bombproof calm hose. I have also asked the seller if there was anything wrong with the horse which he obviously said no. The seller brought the horse to Cape Town. The horse came the Monday and the weekend when I wanted to ride the horse I noticed that the horse was not calm at all. I called the seller and told him that there is something wrong with the horse and that the horse has got stallion manners as the horse wants to break out of the paddock and be with mares. He then told me that I must give the horse time to settle. I agreed and left the horse. I then got the VET out to check if there is not maybe something wrong with the horse which the VET then informed me that the horse has got numerous sarcoids and that it will cost me 10 000 to medicate the horse. The seller agreed then to buy the horse back. I arranged for transport and now that the horse is back with seller he does not want to give my money back. He says he is going to sell the horse and then pay me back. I told him that no one is going to buy the horse but he insist there is nothing wrong. His nr ***