Neglected service and un willing to pay cost

They neglected my car whilst they' were filling petrol and doing checking in 2018 on the 14.of December. Their petrol attendant left my car water bottle enclosed and he closed the bonnet . On my arrival from bathroom he claimed that everything was fine . Only to find out th he didn't close the lid and led to overheating and the top gasket blow.eglen up. They're not willing to paying the damages repairs funds that costed me around R28000