Zero stars for claim payment

If I could choose zero stars I would. Obtained telephonic approval to visit a service provider and now Discovery medical aid is refusing to pay the submitted claim as the service provider (optometrist) is not on their network. I know they aren’t, that is why I obtained approval! Even though all their calls are recorded, they apparently cannot trace the call I made BEFORE I visited the service provider to obtain approval (which approval was provided, as I have a optometrist benefit) that the claim will be repaid, how convenient? I have the date and time of the call, screenshot of my call log and advised them of same, which seems to make no impact. The call agent also does not keep his word to return with an update (Jade Abrahams) and only states “my superior must advise”. I have every intent to explore other medical aids as your poor service leaves a bad after taste.