"Appointment system"

I’m absolutely fuming. My daughter has braces and had an appointment at the orthodontist clinic where they has stressed the importance of being seen regularly, on time. My daughter missed school in order to get to the hospital only to be told her appointment had been cancelled. The staff claimed they had phoned to let us know but I know I have never received a call like this, why would I take my daughter out of school if I did not need to?

A new appointment will, apparently, take a few months. This is unacceptable when my daughter needs to be seen on time. I’ve tried to get through to the appointment system but it goes straight to an answer machine.