Refused Car key after service and had to pay for their negligence

I took my car to Kelston Jeep on Monday 28 October 2024. They took the car and serviced it without calling for authorization from my warranty service provider. I took it back for a return job on Tuesday 29 October as the warning lights weren't fixed. Upon getting there, I was then told I have to pay cash as the service provider rejected the claim..I then enquired if authorization was obtained, that is when the consultant advised she forgot to call.I spoke to the service manager,she didn't assist instead she insisted we pay for the service cash. They refused to release the car until we decided to pay..I then called the branch Manager Karen Muller who was supposed to get back to me with feedback and has still not contacted me till now..