Disrespectful staff member

So I go to protea gardens kfc to buy food on the 1st of June around 6pm. After placing my order I went to shoprite to buy something since it was full at Kfc. When I came back I find that it's only one person giving out the orders who wss focusing on the Uber eats orders more than the rest of us. The lady who was in front of me started a conversation with me saying we won't go anytime soon, I commented back saying it seems so, then the lady who was giving out orders started a comment saying "why do u make us work overtime" I asked how do u mean, then she started asking and shouting why did we have to go to shoprite cause our orders came out long ago and now she has to pack and unpack for us. I became so confused because I don't understand y would she have to pack and unpack food which I already paid for cause if the order is out you just put it aside and wait for me to come collect it. I even forgot to tske her name.