Heck no, you weren't wrong. I did the same thing with a doctor appointment a few months ago. After waiting for over 1 hour, and seeing people still ahead of me still waiting, I told the receptionist I had another appointment and I couldn't wait any longer. So she said - let me reschedule you now - I said no and I would call later and make another appointment. I never did! I didn't even get so much as a feeble attempt at an apology. Yet some doctors reserve the right to not see you if you are more than 10 minutes late??? What's wrong with that picture?