Car not roadworthy sold as roadworthy

I bought a Volvo from Zido Cars Benoni on the 1st. They told me the car would pass the roadworthy test as they already put it through the roadworthy test. But when test driving the car, the engine light was on and went off after a while. There was even a Dekra roadworthy sticker on the car. The engine light never came on again. When I took it to Dekra for the Roadworthy on the 13th it did not pass because of the engine light, oil leak on engine and oil leak on transmission as well as the bushes on the control arm. When phoning them, they say it's been too long, it's out of their hands and I need to fix it myself. They should not lie and brag about the cars being roadworthy if they are not. And they should pay for the issues that prevented the car from getting the roadworthy certificate