Attendant broke my car

I attended Engen service Station strydom park on a Friday after work the 10th May 2024, so I did a full check on my car as always but this time the attendant left the cap under the bonnet open which caused overheating and broke my car completely to a point it needed to be towed. There wasn't any water in the car on Sunday when i got stuck at midrand. I don't know what he did to my car but it caused major damage. Damage to my car caused was over R15000. One thing good he had done was find a nail in my Tyre.