Engen Garage Chiawelo Service Station - Verbal/insults attack

I dont even know where to start, I was emotionally abused this morning by the Engen team member who actually insulted me infront of all customers cause i asked the guy that was assisting me why he leaves me with my bank card to another petrol pump! so this happened around 7:45 today, I always use Engen Garage cause i like Engen garage but after today i dont think i will ever trust being in that service station ever again. So this guy came to me asking how much petrol i needed so i told him i had another car behind me that i need to use the same card to pour petrol. So he said it fine then he asked for my card as he said he was doing calculations of the 2 cars, which i gave to him. but then he disappeared on me going to pour petrol to another car not even the one i was with from a different pump with my card, and at that time i couldnt see where he went and my card can also tap. So i called on him asking him to bring back my card cause i knew that what he did was not allowed that you could move from a customer to a different pump with someone card. so when he came back i asked him why he left with my card so he said* sorry ke* to me that was rude but anyways he said i must move my car as he needs to service the other car i was with. so i moved allowing space for the other car then i got out of the car to make sure that he pour petrol on the car am with, so then am chatting with my mate saying i dont understand the service here cause this guys doesn't even seems sorry or apologizes in a right way to me and this lady who works for Engen started talking back on me saying why am i accusing this guy of taking my card cause he is not gonna tap my card anywhere he is not a ***** and how dare I think that people that work for garages are poor and it people like me that are selfish and think they they work for service stations cause they are pool. Then i tried to explain what happened then another guy came working for Engen still saying am selfish cause they guy who was helping me apologized but am making a scene who the hell do i think I am with a car full of tissues and had no money cause am selling these. it was actually so bad that everyone at the service station was actually looking at me cause I was attacked by these 3 individuals. They were screaming so loudly at me telling me that i dont have such a nice body to actually think of myself so much. i must admit i did say things cause i was so angry of being attacked like that. They even told me they dont care if i came back to this garage or not cause there is a lot of customers. it was so bad am very much traumatized by these actions and thinking of opening a case against these individuals. How do you actually say things like that to a customer?