selling me someting I don't own and didn't want

Have bought my second vechile and mfc has helped me again by giving me finance. But unfortunatly the dealership has taken me for a ride again. I didn't want a tracker device but they said it was already fitted and the contract was already there so I tought it was best for me as I do I have the. Device and its paid for 36months. But when I contacted the tracking company to find out how it works they said there is nothing fitted and have to arrange for fitment. As I don't have this device I would like the dealership to request a new contract without the tracker. But I have been unsuccesfull with the dealership as the contract has been signed and they have received the money from the bank for something I don't own.