Claims poor service

I'm tired of this query, I have sent manual claim and all necessary documents required but still it partially paid I have called and got tired. I have been asked to fill a PMB application form but which states all medication already paid but they choose to approve one with no valid explanation. Application was sent on 4/july/2023.***, ***,***,***,***,***,*** authorized code ***6 pmb code 53N the approval didn't state anything about rejection of other medications and I was advised it's one thing. I have paid cash and send proof but that was useless.