Caltex germiston

I went to Caltex Germiston Saturday night the 26 of may to get diesel in my Nissan X-trail. My husband asked for 200 rand diesel and presented the bank card for payment when the man helping us said the card machine doesnt work. My husband went and withdrew money from the atm on their premises at 22:42. Where the man put the "diesel" (petrol). We went straight home from the garage and the next morning when we got into the car to drive it cut out after a few meters. I then went back to caltex to ask for surveilance video or a slip to see why the man put petrol in instead of diesel. On arrival the cashier said the manager is not in and gave me his number. I phoned him and asked for his help with that and he said to come back the monday morning because he was to far away to come in to the garage. On monday morning the 28 th of May i went back and spoke to the manager. He took my details and said it will take a while but he will phone me as soon as he went through the surveilance and stuff. After a few hours the manager phoned me and asked for my adress because he wants to send a mechanic to come and look at the car. I gave him my adress and the manager send the man who put the petrol instead of the diesel and a mechanic who confirmed that there is petrol instead of diesel. The man then said that the manager said that caltex wont fix my car and that he must fix the car. I just want to know what to do from here and why caltex wont take responsibility for that mistake.