My car was towed to the panel beater in a good mechanical condition, but now???

On 06 Aug 2023 someone bumped into the back of my car. Mon, 07 Aug I drove the car to and from work (70 km) - I have travel log to confirm that. The same day between 1:30 & 2:15 I received a call from a towing company that they are coming to tow the car to the panelbeater. I called Miway to confirm if they arranged for the towing and I indicated that the car is drivable. Miway insisted that the car will be towed. It was towed on 07 Aug, on 29 Sept I called Miway to enquire on the progress of the repair. I was told there's a mechanical problem with the car. On 02 Oct I sent an email to Miway complaining of 1. the panelbeater was taking long to repair the car 2. when the car was towed to the panel beater, it had no mechanical issues. Miway only called on 12 Oct (after I sent a follow up email 09 Oct), the caller confirmed there is a mechanical problem with the car and I am liable for the cost. I then lodged a complaint with Hellopeter, an assessor called and offered to get a second opinion with regards to the issue but I will still be liable for the repair cost (mechanical). I declined the offer, as it won't change their stance that I will be liable for the cost. Today, 20 Oct I received an sms from the panelbeater that the car is ready for collection. The extent of the problem is huge, the speedometer cant exceed 10km/h. My cat was towed there in a good condition, I really need my car the way it was towed to the panel beater.