Discovery refusing to pay for Ozempic on Chronic

Discovery has approved my Ozempic for 2 years running and now when my doctor has requested the higher dosage pen(3ml) cos I have not been able to hit my targets on HBA1C or weight wise they are refusing to even pay the same portion of R950 towards a R2700 pen. I am willing to pay something in cos it is expensive but I am Type 2 diabetic and clearly need it as I am overweight and now also have a heart stent and kidney issues. This is just not acceptable!!!!!!!!!!!!!!!!!!!!!!!!!!