Customer blamed for Waitress Forgetfulness

I visited this outlet during their 50th birthday sale. Took my family for a treat. The waitress took our orders, and we asked for spinach sides to our steaks/ribs. She brought a side of chips and forgot one of our orders and said that she was sorry, which we accepted. I then ordered a Caramel Popcorn Gourmet Milkshake, instead the waitress brought me a Chocolate one. I told her that I didn't order it and she said that it was her mistake and she forgot my order. She told me that if I don't accept it then she will have to pay for the mishap out of her own pocket. However, since I don't like chocolate, I pleaded for her to correct the order. When she came back she brought the same chocolate gourmet milskshake but with some caramel sauce on top. I requested to speak to the manager since I felt she was trying to fool me into accepting the wrong order. When the manager arrived, I told him that it was not a Caramel milkshake and without any hesitation he said he will correct the order. I am totally disgusted by the bad service from the waitress, and will probably not want to go that outlet again because of the service. The manager was awesome though - good job on him.