Unprofessional

Last night whilst visiting a family member in hospital I went to Mc Donald's Campus Square to order a tea and coffee for my wife and I. My order number was 359 and on the board it displayed that 354 to 358 were being prepared. 5 minutes later I saw that my order was being prepared and another 10 minutes later I still had not received my order yet 360,361,362,363 and 364 were handed their orders which were meals. I then approached the lady at the counter to enquire how long it takes to make one cup of tea and one coffee. I only received my order 3 minutes later. Being that I needed to get back to hospital I didn't check my order until I reached the hospital and only then realised having ordered coffee with milk I was given black coffee. How does one get such a simple order wrong and how can it take that long to prepare the order. I am disgusted in attitude and unprofessionalism displayed.