KFC(Kentucky Fried Chicken)

On 1/20/20 I ordered from the drive-thru at KFC. While I tried to order the employee continued putting me on hold, I had to keep repeating my order because she keep laughing with others in the background. When I finally thought my order was complete I was told that it would take 10 minutes for my order to be ready. I said that I would pay for my order then come inside to pick it up. When I paid for my order she had given me the wrong total because she wasn't paying attention. When 10 minutes was up my mother and I went into KFC to pick up our order. It still wasn't ready, but did come out a few minutes later. I noticed on the receipt that she messed up the order and did not give us what we ordered, which was a full meal. Another employee, a young man, apologized to us and provided us with the missing items and said "don't worry about it". The woman, who said her name was "Lisa" said that we owed her $3. I said "no" because she messed up the order after we repeatedly told her what the order was but she was too busy laughing and not listening. I told her the young man had already helped us. She insisted we give her $3 and would not acknowledge her mistake. She then accused us trying to steal a drink and cookie. This lead to a huge argument. We were highly offended by her false accusation. The manager stood on the side with his hands in his pocket and did not try to help the situation. It appeared as if he was hiding. Before taking legal action for defamation of character and accusing us of stealing in front of workers and other customers we are requesting to speak with a GM first. To be accused of stealing on top of the poor customer service is inexcusable. I told "Lisa" I would be contacting corporate and she said "So, contact them if you want" and smiled. She obviously is used to behaving in this manner. The manager needs more training since he did ABSOLUTELY NOTHING to help the situation. The only person that tried to diffuse the situation was the young man.