I'm going to be the Ass here.
You made the appointment at 12:30 correct? What have you learned (should have learned) as you were growing up about showing up EARLY for appointments?
I've seen how busy these stores get and if your name is called and you're not there, they move on to the next person. It's that simple. Nobody else should have to wait or adjust their time because you were three minutes late.
If it was that big of a deal, you should have asked to see a manager. Not post here about how you were late and people should make an exception for you.
Hence why it's call an appointment. Lol