Dentistry with Fedhealth

I have been with fedhealth since 2017, upon taking the plan I made it clear that I have a child living with a special condition. At age 7 my child needed dentistry assistance which needs to be attended for in theatre which they refused to authorise as it was a private practitioner. And now 4 years later we finally got one that is on their network and they are still rejecting to assist the young boy who is really struggling with his teeth. We have sent motivational letters from his doctors explaining and pleading for assistance but still they refuse to assist.After 8 years of paying , this is disheartening. I am forced to cancel my plan. Spoke to an agent named Demma and she laughed at my situation. What kind of service is this ?