4 months later and car still not repaired properly

I met in an accident on 7/12/2019. Discovery arranged for my car to be towed to a panel beater and repaired. It was a side smash whereby another car drove into the side of my car. Majority of the damage was to the front left of the car but there was repairs to the rear passenger door as well. The repairs were approved and done. I collected my car on 17/02/2020. This was already 3 weeks late due to delays at the panel beater. Immediately I noticed that the car was making a noise. Phoned the panel beater and sent Discovery email. Long story short I have taken my car back to the panel beater 3 times and my car is still shuddering when I drive. Last week the panel beater suggested that I take my car to TWT for wheel alignment and balancing (at my cost) . I did that and TWT informed me that both the rear wheels are buckled and they also identified that the car was shuddering when you brake. This was not picked up by the panel beater nor the assessor from Discovery. When I call the panel beater he says that he needs approval from Discovery. When I email Discovery they state that I must contact the panel beater and IF it relates to the accident they will pay. Is it my fault that the assessor did not inspect the rear wheels or if the panel beater did not repair the car properly. I complained about the noises etc as soon as I picked up the car from the panel beater. Everytime I ask for someone senior to contact me from the claims department I get the same email to take my car back to the panel beater. How may more times do they expect me to take my car back.