Unfairness

I'm so angry with my insurance company iwyze. When I took their policy. I was told about only R4500 for excess. My car was in an accident but it was someone's fault not mine. I paid the excess and my car was released to me. Now after weeks I get a call from the panel beater telling me that my insurance did not pay everything. There's an amount outstanding due to me but my insurance never bothered to tell me about that. If I pay my premiums and I have also paid excess, why do I have to pay extras?