spicy biltong burger

Went to mcdonalds got a spicy ranch just before the rugby started, came home was so hungry opened the box and the Patty looked like a junior burger only super crispy, was hungry and couldn't go back immediately as I would miss part of the game so I ate it and phoned only to be told that the only way they would replace it, would be if I returned a half eaten burger. So basically they getting away with giving me a piece of ****, which I might add is one of their most expensive burgers, just because it would inconvenience me too much to go back immediately. If this is fair or the norm for this franchise then please let me know so I can never return to it.