Discovery Health PMB Dispute

We app**** for a PMB at the beginning of 2018 which was granted for our son. Once this was almost all used up we contacted Discovery to see if we could apply for more. They said yes and we went ahead and app****. We received confirmation that we had 3 more sessions approved, but once the medical professional submitted her invoices they were declined and Discovery changed their minds and retracted their approval of more sessions. We have been back and forth with emails and phone calls to try and get this resolved only to be told that this is their decision. We find it totally unacceptable that once they approve something that they can then go ahead a change their minds.