Being called negligent for carrying a cooler box on a hot summer day

On Saturday 3 September 2022 we had to go to my nephews 5th birthday party and we packed our snacks and cooler box with ice and water in the boot of the car along the way the car just stopped and would go to neutral and water kept dripping at the back under the car we called the sos for help only to realize after getting the car to my brother's house less then a 2km that the cooler box broke and Sunday the car was collected and today Tuesday 6 September 2022 im told that motor plan is saying it's negligence and won't fix the car. Who doesn't travel with a cooler box , drinks and snacks in their car when going out to a summer party. Is it considered negligence carrying or having a cooler box. I'm not happy with the reasoning everybody puts their cooler box in their car I am not special. Why should I be punished for something that was beyond my control. I paid R10,500 so I can get my car home and I'm labeled negligent

*** Mrs Matee