Discovery Health penalising me for a shortcoming in their system

I am a member of Discovery Health on the Classic Comprehensive plan. I received an email from Discovery Debt Administration recently, stating that I owe them close to R4000 for a claim they received from Medipost pharmacy, which was subsequently reversed. I phoned in and spoke to an agent called Tanya. She confirmed that the claim was revered and that no amount was paid to the pharmacy (Net effect of reversal is R0 - as expected). However, she maintained that I nonetheless should Pay Discovery the amount as it brought down my self payment gap. My response was that, since no actual money was transferred to anyone, simply adjust the self payment gap. But she continued on that the money should be paid as they cannot adjust the gap on their side. I asked to speak to her supervisor, to which she agreed. She placed me on hold for 5 minutes, and then cut me off.

To my mind, the above situation is similar to star bucks points you get every time you make a purchase at Star Bucks. These points don't mean anything until you actually use them. Using this analogy, if I were to order coffee at Star Bucks, and the sales person allocates points for the purchase, but I then cancel the transaction before the order is executed, according to Discovery Health's logic I should still pay Star Bucks the money equivalent for the points awarded - even though I have not made use of the points (and also might not even in future).

The short-sightedness of the agent, and the fact that she cut me off, is disappointing to put it mildly. And Discovery Health's "explanation" to the above situation makes no sense. I will be escalating this further.