Mcdonald's Woodmead Bad Service

I ordered food using the app and the cashier did not know what she was doing and gave me 2 different amounts not matching the price on the app. She then called the shift manager by the name of William who refused to change the price and refused to assist me and the cashier. The other staff members kept telling him that the app has the correct price but he was not interested. The manager was rude to me and when I told him that I will lay a complaint, he refused to give me his name and refused to process the order as I will not have a receipt to complain. He walked away from me and i had to wait over 20 minutes before I got assistance. I was only assisted by the restaurant manager by the name Lucky and the shift manager did not even bother to come back to me and apologize for his rudeness towards me and for wasting over 20 minutes of my time.