Where was the class, and why did you have to phone the instructor? Did you arrange the class? Whoever organized this class should have phoned the instructor and all fees paid, returned on the spot!
Technically she is running a business (she rents herself out as an instructor) and that's no way to run a business think twice (and hard) on hiring her again. So unprofessional.
Here's my biggest pet peeve:
Between work, home and hobbies, my time is very valuable (and scarce). This goes with every appointment I make (try to make the "well" in advance). They insist on an appointment (oh ya, they will charge you if you miss) and I'm finding more and more do not honor the appointment time. I don't mind 5 - 10 mins late, but after that I start to steam. My time is just as valuable as their's. Do I get to charge them? Ya, not happening.
End of my "pet peeve" rant