Not just Doctors, but dentists and that whole group have major issues with their "customers". My dentist requires i cancel an appointment by calling in with 2

Not just Doctors, but dentists and that whole group have major issues with their "customers". My dentist requires i cancel an appointment by calling in with 2 working days notice. Failure to do so can result in a charge. She has also called to reschedule my appointments with under one day notice??? Last time she did this, i told her there will be a short-notice cancellation fee. She refused to pay, and refused to recognize the irony in what she was doing. She also texts you to confirm your appointments, but the only option you get is to "accept" - you cant respond to cancel/reschedule.. this must be done via the phone only???