What's a Refill?

This afternoon we decided to do lunch at McDonald's. We have a McDonald's only a mile down the road at the first major round about south of Glinton. We've done the drive thru a few times and that took some getting used to because you obviously drive up to the other side. Over here you actually talk to a person to give them your order which is quite lovely. The hard thing is to realize when you are ordering your 4.50GBP quarter pounder with cheese that it's actually costing us $9. I've taken quite a liking to the Chicken Selects and they don't have your typical Ranch, Honey Mustard, and BBQ sauces, no they have Smokey BBQ, Sweet Chili, and Brown Sauce. Well today Kevin and I split a Chicken Selects meal and we downed the Coke we had been sharing and we were still pretty parched when we finished off so I attempted to get a refill. Now I say attempted because typically in restaraunts in the UK you don't get free refills on really anything. I walked up with my empty cup and asked the chap behind the counter how much it would cost to get a refill on my Coke. You thought I started speaking a foreign language to him with the look I got. I then went on to explain that I wanted to get more Coke in my cup and asked how much would it cost. He asked if I had Coke left in the cup, I said no, and he asked "What is it that you want?"...."I want you to refill my cup with Coke and I will pay for it." He proceeded to ask if I wanted a large and if I wanted a new cup. We came to a consensus that I would just buy a brand new cup of Coke. I filled Kevin in with my conversation as we walked out of the store and we just marveled at the idea that guy didn't understand what a refill was.