Missing carton, insurace does not want to pay full amount to replace the items

I am quite livid and frankly fed up with the service (or lack thereof) that I am receiving from Stuttafords. I relocated from Johannesburg to Cape Town in October 2019. Very unprofessional service I received right from the very start. Total lack of communication. Nevertheless my items were picked up after much issues on the day of moving. As part of my shipment I had 2 wardrobe cartons. Upon arrival in Cape Town one wardrobe carton was missing. This was reported to the unpackers and the company on the day in questions who said that they will investigate. The unpackers unpacked the one wardrobe carton which was received. It should be noted that the other wardrobe carton that was not delivered was practically all my clothes. After much following up on my side, I was informed that they could not find the box. Clearly negligence on their part. Apart from already being inconvenienced because I had no clothes, I now had to start the claims process. This again required numerous follow ups from my side. I provided the claims department with all the necessary documents which they forwarded to the insurance company. The total claim to replace all the items in the box was clearly indicated on the form as per the inventory. It is now more then a month later and the insurance company is offering me an amount that does not even cover half of my claim. According to them their policy is that they take the total amount for clothes and divide it by the number of boxes of clothes. Totally illogical! Some boxes have more valuable items then others which was clearly indicated on the inventory list. It should be noted that nowhere in the contract or policy that was provided to me by Stuttafords does it indicate anything to this nature. The insurance company says that they can not do anything and that I must speak to Stuttafords. The negligence is on the part of Stuttafords for not delivering my carton. They should ensure that this matter is sorted out with the insurance company but they have been no help at all.