Cash back and settlement issues

I have bought a car with the Omoda Boksburg, the sales gentleman was good, but I experienced troubles when they had to settle the other car I have, the agreement was that, when doing application I will include the settlement amount of my other car to the new loan and they will settle it. And I was approved and I collected a car .the settlement of the other car should have been settled after I have collected the car and that hasn't been done and I haven't been given a valid as to why the settlement hasn't been done, I've been to the the dealership twice and they promised that everything should be in order on Monday but nothing has been done, I called the Omoda head office but still I haven't received help and I've also called the dealership many times and I have requested to talk to the principal but he's too busy to attend to clients complains, they said he will call but he hasn't and also I've been promised cash back and I haven't received it, it been a month now since I collected the car and none of the things I have listed here have been sorted, so disappointed with all this now I have to pay for my other car which they should have settled because the money it's with them, wouldn't send referral to them after all this I've been very understanding and patient with them