Payment rejected for authorised treatment

I got written approval for treatment on 26 May 2026. After each appointment the payment gets rejected by Bonitas and I have to struggle with multiple calls to the call centre. The first payment was eventually made, but now I am struggling with Bonitas to pay the second appointment. I have confirmation on multiple phone calls that the treatment was approved as PMB and that the payment will be made, but then it just gets rejected again. The healthcare provider is now asking me to settle the bill.