Bad service for a 3rd party claim

On the 25th of August 2017 a company vehicle bump into my parked vehicle. We went to the police station and open an accident report. On Monday the 28th of August the person who bumped into me gave me a claim number and the telephone number for Out surance. I gave the information to our representative from our insurance. Almost two months later we still struggle to get authorisation from Out surance to fix my vehicle. After my husband phone them they said they still need some documents. We send it to them for the 3rd time. They did an assessment based on the documents and photo's we send to them. They send the assessment on what they will pay to their client. It is R4000 less then the cheapest quotation we got in our town. We phoned them and explain that we want to know why their assessment is less than our quotations and when they going to pay the money. The person said that we must phone their client to get the money from them because they will pay the money out to their client and that their assessors know what they do and we must except what they said on the assessment. On their assessment they had a bumper cover but my vehicle don't even have a bumper cover it is a complete bumper. They did the assessment without seeing the actual damage on the vehicle. This is not acceptable because I am not guilty of anything. The person bumped into my parked vehicle and now I can't even fix my vehicle with the money they are willing to pay out. We send an email to say we don't except the assessment but we don't get any reply from Out surance. Can someone please assist us?