Painstaking claims process and shortfall on claim payments

I have a motor vehicle claim that has been open since September. The claim was initially approved but with a shortfall of R7k because Discovery did not believe the quotation I sent (even though it’s from the only official JLR dealership in the area). Further damage was discovered on the vehicle which was a result of the same accident, which has added another R50k to the repair costs. I am now out of pocket for R53k plus the R3k excess and they are just ignoring me. Every time I call, I get promised a call back, which never happens.