Bad customer service

I've cancelled my medical aid with discovery and my withdrawal date is the 28/02/2022 however, ever since February has started every time I have to consult I must call Discovery for authorisation because when the doctor confirm they decline my claim, I'm spending too much on my airtime wherelse I've been paying them continuesly, please advise as to why do I have to struggle to consult, on Saturday I went and consulted with a Dentist and today to patch my teeth and my claim is reject which means I must pay the dentist, please advise why is my claim with Dr Machaba Machaba Inc is declined. Please contact me urgently