King Price is useless

I was involved in a car accident on the 18th of June 2022. My claim was registered on the 19th of June, the assessment was conducted on the 27th of June and the claim only authorised on the 28th of June. They were very efficient with assisting me with a courtesy car which I collected on the 20th of June. I was receiving updates on the repair stages until the 8th July. Thereafter, I had to call the insurance to find out the status of the vehicle and when it would be ready as my 30 days for car hire was to lapse on the 20th of July. I have been calling the insurance asking them to at least provide an estimate of when the vehicle will be ready. I was told that they cannot give me an estimate as the king price assessor had under estimated the damage, and the repairer had to wait for authorisation before they could proceed with ordering the new parts. As such, it could be ready in August, or September - basically they don’t know. However, they assured me that they would call me to give me an estimate time. I have not received any feedback from them. The most frustrating part is that my car is covered under the business insurance as I utilise it for work. King Price is not even willing to extending the car hire duration even though the delay was caused by them and their service provider. Instead when I call I’m told about policy and they are refusing to let me speak to a supervisor. How am I expected to make any arrangements if I do not know when to expect the vehicle? How am I expected get to work? I cannot afford to hire a vehicle. How long will I wait for them to give me feedback? Am I expected to call everyday and beg for feedback and be bluntly told that I can’t be assisted? I was hit by a drunk driver, why does it feel like I’m the cause for all this, including the delays? I am very frustrated and honestly don’t know what more to do.