If you cancel your booking before the appointment has started, depending on the cancellation policy, you may or may not be charged for the booking.
I did not turn up for my appointment
Your service provider has the right to charge you for no show. Waiving the no-show charges will be at the discretion of your service provider.
The service provider did not turn up for the appointment or was double booked
There may be instances where the service provider overlooked the appointment schedule and/or double booked. In these rare instances, the service provider should have cancelled your appointment or rescheduled. You will not be charged for these rare instances.