Wrong faulthy debt

In 2020 I app**** for the hospital authorization from Discovery. Discovery approved all the codes and procedures before the operation. After the operation they did not want to pay everything. I logged a query and Discovery went to listen to the call when the original authorization was given to me, because of that they made the payment to us. I paid the money over to the doctor. In 2021 they took the authorization back and are threatening us with blacklisting I still have all my documentation and proof that Discovery gave the approval. I have written to Discovery without any understanding.