If you bought it MIB, contact playmobil.. they should send you the correct horsys and the bridle..
I, in fact, already contacted PM. The outlet store where I purchased the set is also home to Playmobil Canada's head office, which, in turn, is home to the massive parts department. On my latest visit, which was after I bought the set, I told the clerk about the missing bridle and wrong horses. He scoured the parts department, but returned empty-handed, saying that none of the new-style horses in that particular set were in stock. (He did, though, give me the missing bridle). So, I left my address and e-mail, so that when a delivery of the correct horses arrived, he could send some out to me.