No patty on burger

I went to McDonald's in Gandhi square in Johannesburg town, had 30 mins left of my lunch time. I ordered a plain big mac with extra cheese, and a coke with ice. I collected my order rushed back to work to eat only find out theres no patty on the burger !!! Only bun and cheese ? How on earth??I have pictures of this, it is absolutely pathetic! I didn't even have time to take it back and no rub salt in my wounds, the coke tasted like coke zero, and I ordered a normal coke!!!