Bad service

I traded in my car in Hyundai Benoni for a Hyundai I20, I was given a car that is not road worthy. I did a follow up after a week on car registration, only then I was told to bring the car for roadworthy test. I took the car in for the test and I was promised they’ll get back to me with plate numbers. After another week I do a follow up, again I’m told to bring the car for roadworthy test and I don’t understand how, even now I’m driving the car with a temporary registration that is expiring in 2 days. I called so I speak to the manager, they refused to put me through to the manager and said I should sort it out with the salesman “Sizwe” that is not delivering to any of his promises. I’m frustrated as we speak and I don’t know how to get this sorted because the salesman I’m told to speak to, is failing to deliver.