Signed the purchase contract and offer to purchase was accepted and paid cash, now I can not get my car

<p>Purchased a used Sonic Sedan from Reeds N1 City. The car was advertised for R145 000, I took the vehicle for a test drive and decided that we will take it. The paper work was done offer to purchase signed and accepted and full payment made, now they tell me they sold me the wrong car. They didnt have the correct year model on their system ????</p> <p> </p> <p>The offer to purchase contract states ' The vehicle remains the property of the dealer, UNITIL full payment is received' and full payment was made to them so who is the owner ?</p> <p> </p> <p> </p>