Oh, they understood you alright. I've found that most young people in Quebec understand English just fine, but it's just not PC to admit it.
I stopped once in a convenience store right up the road from St. Jean in the town of La Prairie (Mario Lemieux's hometown). Whenever I traveled up to Montreal I had always stopped in this same store to withdraw some Canadian cash from their ATM, but when I got there this time I found out that they didn't have an ATM anymore. I asked the kid behind the counter about the ATM.
I didn't speak a word of French, and the kid behind the counter never said a word in English, but after 30 seconds of "conversation" I somehow knew that I was supposed to walk across the parking lot to the new bank that had just been built next door. LOL.