Bad Reprasentation

I did a trade in on a Toyota Dakar 3D4D 2015 model 2x4, for a Renault Duster 1.5Cdi. They offered me R350 000, which I took the offer<br> After paying the price of the Renault Duster withe a trimming kit and smash and grab, a settlement of R74 000 would be transferred into my account. I signed the deal, and since the I've had endless excuses, and lies why the trimming kit hasn't been installed and there are extra expenses that was not included in the settlement. So far they have transferred R62 000, which on signing of the contract and purchase of the agreement, they still owe me R12000, which they refuse to pay.