Bad service

Hi I was in an accident with a customer santam the company vechile bam in too my bakkie it was on 16 of January from that day iam the 1 has been call them and check in on my case I only received 1call from santam after I was the 1 calling in and my airtime running out yesterday I received a email too tell me form that I need too sigh for half of the amount that the panel beaters invoice me for I call in julia told me that that is what the assessor value the damage on where he can get the parts which he send too the panel shop last week. I check the invoice which santam email me and all the stuff they want that panel beater must put on my vechile is secondhand stuff and my bakkie is still new with 23k on the clock this is so bad that insurance companies are bullying our normal bread winner where must I get the difference in amount too fix my vechile now