No Substitute

I'm not a fast-food junkie, but I do enjoy going to one of those joints once in a while. Tonight, I stopped at a Burger King for a quick bite. After a brief greeting from the girl behind the counter, I placed my order:

"Hi. Can I have a number one meal?"
"Do you want cheese on it?"
"No. Can I substitute fries with a small chili?"
"No, we don't do that."
"Oh, then I'll order it separately."
"Wait," she waved to a girl near the kitchen and asked "Janet, can we substitute the fries with chili?"
"No," she said to me after the other girl shook her head.
"That's fine. I'll order it separately. I'll have a Whopper sandwich..."
"Do you still want your number one meal?"
"No, forget that. I'll have a Whopper sandwich, a small chili, and a small drink."

I don't know what's going on, but we used to be able to do that. I'm guessing the girl was new and she thought by my saying "substitute" it meant I could get a small chili with the same amount of money. If she were smart enough, she could just say it'd be more money if she did that. Anyway, at least she spoke English(*1) and there was no problem talking to her.

(*1) Yeah, a while back it was all "immigrants" and it was difficult to communicate with them....