Krystal review: Customer service

This Krystal's has the worst customer service I have ever seen! I ordered 4 Krystal's and a chili cheese fry, which was $9.19. (I should have known something was wrong since they didn't have any customers in the drive through). When I got to the window, I told this young girl named Tyania that I wanted to get the burgers with onion only. She looked at me and told me that they had already made the burgers. I told her that for this price, I wanted onions only on my burger. She got really angry and told one of the workers that I had an attitude. I was simply explaining to her what I wanted on MY burgers and NOT what she had already ready. She gave me my order then slammed the drive through window. I know we are in the middle of a pandemic and good help is hard to find, but the workers need to be properly trained on how customers should be treated.