Disgusting attitude

On the 19 August 2020 at exactly 12H15 I went to KFC Maitland drive-through and I bought 4 streetwise 2s. When I received my order I realized there's only 3 boxes of Streetwise 2 and not 4. I called out for assistance from the window and a lady by the name of Zintle came back. I explained that there's 3 boxes and not 4. She rudely tells me to step out of the drive through as she will only be able to give me my 1 order in 10 minutes as they are cooking more chicken. I asked her why does she not apologize for giving incorrect order, she said she yelled and said she will do no such. A male guy came claiming he's the manager, apologized and immediately gave me the balance of my order. I asked him why is the lady rude and not apologizing herself and he said he will speak to her in private as she refused to listen to him as well. I have never felt so belittled and disrespected in my whole life. I work in a customer service environment and I service my clients well hence I expected Zintle to do the same. She brings no value to KFC and she lacks customer services. I will not bother to go there again as the manager himself could not call her own staff into order.