We went to the location she has worked at for the last 4 years (but is on a leave of absence right now), and ordered the Two can dine, and an additional sausage mcmuffin. We got our food and started driving off when she asked me to hand her the sausage mcmuffin, I looked in the bag and saw there were only 2 egg mcmuffins in there so we were missing one sandwich (the sausage mcmuffin). I tell her this, and although we were not out of the parking lot yet, she says theres no time to go back, and will think about calling back later to have it written in the book.
We pass another McDonalds on the way (and have our receipt and bag with wrappers etc.) so she pulls into that drive thru to talk to them, and explains we went to a different location ordered and were missing a sandwich and have the bag, wrappers and receipt to prove it, can she get the missing sandwich. The lady tells her that we have to go back to the original location and she can't do it (which my sister knows is untrue), she tells the lady she understands where she is coming from, but has worked at McDonalds for the last 4 years and the first thing they teach you in team leader class is to give the customer what they want and correct mistakes. The lady does not respond and is now ignoring us so we drove away. I do not think my sister has followed up yet, but was really upset with the girls attitude, and was thinking about reporting her.
Slightly unrelated: the rest of the drive to school my sister was telling me stories of times the customer was clearly wrong in complaints she dealt with, but she still gave them what they wanted. Some examples: her store is the parent store to a location in Wal-Mart 1 block away so she works at that location sometimes which obviously does not have a drive-thru, and will get complaints from people saying "I went through your drive-thru and am missing......" or "last time I was here I ordered a Fillet O Fish, and did not receive it" (Wal-Mart McDonalds have a limited menu which does not include Fillet O Fish), yet she always finds a way to make them leave happy/give them what they want.