Funny, I had a similar experience at a McDonald’s (what is it with them?)
I took my three kids there for ice cream. I ordered cones for all of them, but asked that one be put in a cup, not a cone, as it was for my 2-year-old. Well, I got two cones and a cup, but when I looked at the receipt, they had rung up the cup as a “sundae, no toppings”. So I asked the cashier about it, and she said it was the only way to put it in a cup instead of a cone! I asked to speak to the manager. The manager agreed that I shouldn’t have been charged for a sundae, just for a cone, and said that since I was charged for a sundae, did I want to add a topping? Well, I explained that I just wanted plain ice cream, no toppings, it’s for a two year old, for heaven’s sake! So, he said, “OK, it’s up to you” and started to walk away. I had to say “Umm, could I just be refunded the difference in price?” He looked at me like I had spoken to him in Swahili, but after a time, he opened a register and refunded me the difference!
I’m always polite, though, and once that got me a refund that I shouldn’t necessarily have gotten (and may have taught my 9-year-old a lesson). She had bought a tavern pipe at a gift shop in Williamsburg, VA. Later, she opened it, and the stem was broken. We took it back to the shop, and the woman told me they couldn’t take it back, because they didn’t think it was broken when we bought it, it probably broke when she was taking it out of the box or something. I said I understood, but politely explained that if I had realized it was so fragile, I probably would have had her get something else instead. I thanked them for their time, and was headed out of the store, when the manager called me back. “We don’t usually do this”, she said, “but you were so polite, I just think we should take it back and refund your money”. Well, there you go! More flies with honey and all that!