Terrible customer service

Terrible customer service I had an appointment confirmed for 11H00 only to get a reminder to confirm the 16H00 appointment. Took my time to correct this and called the receptionist who was not welcoming at all and told me the dentist would be in the theatre that time and my appointment would be at 16H00 or I could cancel it. Why was I not called about this change as the courtesy to check my availability but instead given the time that suits them? They matter, and I don't; that is my conclusion.