Very very bad customer service

I put petrol and checked my oil and water at Caltex Marlands . The petrol attendant did not put the water cap back on and as a result my cars head gasket blew which in turn damaged my aircon. I went back to see the owner Alan but he was not there so left my details with his manager. I have been back 3 times with no luck. The manager told me to sue the petrol attendant. The cost has already been R30 000 the aircon will cost another R21 000 I find it ridiculous that Caltex which is now Astron but with the same owner. They should have insurance for these kind of things.