Slow service and rude attendants

I had a very unpleasant experience at Shell this morning. I arrived at Shell Jamestown at 6:48. There was only 2 petrol attendants on duty but its the peak of the morning. Finally an attendant ,Bertha , came to me at 6:55. She put the nozzle in my fuel tank and went to help two other customers. 2 minutes later she came back and closed the fuel tank. Then she walked away again. Now i started to get very agitated because I only had to pay. She then started to help some other customer. I then asked her whats going on and she got irritated and told me she did me a favor by helping me and I can go and pay inside. Then she spoke in Xhosa to the other customer(could obviously been discussing me). I then decided to start my vehicle because I knew that would get her attention. She then came to me and started addressing me as if i was a child and called me Cici/sisi. I am sorry but the appropriate way to address any customer is mam or sir. She also expected me to keep quiet and listen to her but she was unwilling to listen to me. I am so dissapointed in shell because this is the only fuel station I go to. This is also not the first time that there's only 1 or 2 attendants during peak times.