Really bad customer service

I was at the sasol garage in Newcastle I filled R980 fuel and was going to purchase some goodies for my long trip still ahead I asked the store if I could swop my red bull for a cold one and was not willing to help so I asked for the supervisor he wasnt very helpful either. I drove to the next garage and they were more than willing to assist I purchased goodies for R500 from that store and felt really welcomed. Why is it so difficult to exchange it for a cold one when i am giving business its not like I wasnt supporting them. Ridiculous really. Now after that experience I will not support them anymore.