I have a reward for a free milkshake and asked the lady if i got have the peppermint milkshake making that was fine and she said that was fine but at the window of the drive thru she still charged me for the milkshake.

She might not have known this, but the free milkshake was actually only for the Vannilla, Choc, Cookie, or strawberry milkshake. I'm sure if you called and told them your issue they could help you out.

Probably a mistake. I would have reminded her of the reward for the free shake.