Terrible service I've got

I went to kfc very starving on the 10th February 2019 it was around 17:27... I got a cashier (lungile) who served me, she took my order very well as I ordered a variety lunch box but she never asked me on which soft drink would I like... she finished placing my order and gave me my slip... on my mind I thought that maybe she forgot, she will ask me when she gives me my order. I went to shoprite to buy some stuff when I came back they gave me my lunchbox which I've ordered with cremesoda soft with ice, I asked them who said I wanted cremesoda, they've told me that my slip has cremesoda, asked them nicely to give a coke with no ice... she said they can't exchange the fountain that she gave me.... I failed to understand why she can't change it while she never asked me about my drink flavor... I got a terrible service I must say... if that's how, they treat their customers then I won't I go there again....