Wrong Order

I am very disappointed with the service that I got from Mcdonalds Florida North, I ordered a Big Mac Meal takeaway on Monday and to my surprise when I got back to the office I found this small burger, I asked my colleagues in the office and they told me that the burger is apparently called a chilli cheese burger. I am disappointed because before the lady gave me my order she actually asked me if my order is a Big Mac meal and I said yes, I filled in the rate our service thing on the website thinking that someone will actually contact me but nothing. If Mcdonalds can get such a simple order wrong I just wonder what else they are doing wrong.