Discovery messing around payment for PMB, compromising my health

I have a Prescribed Min Benefit condition for which I get treatment approved annually in addition to having monthly transfusions authorised. I jump comply fully but Discovery is taking my medical savings a week before to pay for the PMB medication AFTER the treatment date (& then reversing it). I assume this is for their cash flow but it means I can't pay for day-to-day expenses and my treatment dates get changed as the pharmacy does not want to release the medication (understandably). My life, and health, is on hold for a week as I try to push through for treatment, I have to book extra days off work and there seems to be no-one to assist with resolving an impossible, bizarre self-created system. No response to my complaints for something that keeps happening! Desperate for treatment and clear processes.