Undisclosed damage on a vehicle and not wanting to take any responsibility

In Oct 2017, I purchased a 2nd Audi A1 from the dealership and before the actual sale, I asked them to confirm any defects on the vehicle either caused by and accident or not. I was given the assurance that the vehicle was never involved in an accident and that there are no defects. They even showed me some report which apparently is prepared by some entity which do thorough inspection on all their vehicles before they are sold. On the strength of this, I then proceeded with the purchase.

On the 16 Nov 2017, I took the vehicle in at Audi Menlyn for them to install a Tracker plus do a proper valet to protect the paintwork of the vehicle. Soon after delivering the vehicle, I got a message from Audi with pictures showing a damaged sunroof. I immediately contacted Mohammed from Hyundai and I was told that they are looking at the situation and that they'll revert back to me the next day.

On 5 Dec 2017, I contacted Mohammed again and he told me that he has escalated the matter to their dealer principal.

I'm at a point whereby I cannot have a discussion with them anymore except for exposing them for what they are.