McDonalds Service is VERY Poor!

McDonalds Cresta & McDonald's Diepkloof Square - Worst service ever!!! They gave me the wrong food twice and on different occasions. Why do I have to check if my order is correct, I expect to get what I asked for - you cant tell me "its a mistake" Its not rocket science!!! How many other clients are you doing this to and getting away with it - Up your customer experience/service guys it sucks!