Please can someone advise us what we can do about this.

We are desperately looking for someone to assist us as we are at a place of not knowing what to do in our situation. In our state of desperation we sincerely hope you will be able to provide us with some assistance on your part. My partner, Phillip McCarthy and I purchased a 2009 Audi A4 TFSI from Yellowstone Auto, Johannesburg South Africa towards the end of March 2019 after being in a very serious hit and run motorcycle accident in December 2018. We needed to purchase an automatic car as my partner is still on crutches as he recovers from the injuries incurred from the accident we had. We took delivery of the vehicle in early Aprl as the seats in front needed some repair and the vehicle was supposedly serviced as well. Sad to say that from then until now we have not had the priviledge of driving this vehicle for as little as 5 consecutive days, because we have had to continuously take the car back to the dealer. We have numerous times requested the dealer to take the vehicle directly to Audi direct so that the vehicle can be fixed properly, but he insists on going to these fly by night mechanics that he deals with as it is a cheap way out. I think we have taken the vehicle back a total of 13 times now and we have just about had it. We keep asking for proof of what has been done on the vehicle but the dealer has not been forthcoming with the documentation. Every time we take the vehicle from the dealer, it has to be returned the same day because the engine light keeps coming on. It has now been 4 months of us paying for a car that we have not been able to drive. We cannot make plans to go away or do anything because we dont have the car. The dealer has been kind enough to give Russell a loan car to drive, but we dont want to drive the loan car, we want to drive our own car. What is the use of us paying for a car that we are not able to drive?. Could someone please assist us in getting this resolved? My partner really wanted this car, has always wanted to drive an Audi and we are now at a crossroad where we dont know what to do. He went back to work this month and he needs the vehicle. We believe if the car had been taken directly to Audi the problem would have been resolved by now. We believe the dealer does not want to spend the money necessary to get the vehicle fixed and we are the ones being disadvantaged here. We believe if the dealer is pushed by you as the brand holder of this vehicle he may do the right thing. After all he has been paid by the bank for this vehicle and now we sit with nothing. PLEASE HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!