The warranty group theserviceport review: Non payment of stove replacing

I had a KitchenAid slide in range mode KESC307HBS8 and I had an extended warranty, now the stove had a short when a technician came and he unscrewed the smoot ceran top said that there was grease underneath of it and said that was the cause of the short. The service company is refusing to pay for the stove because the say that I should had cleaned the stove. There is no way I can remove the top to clean the stove