How dare you charge me a service levy of 20%?

I opted to NOT make use of MedXpress anymore because they DON'T fulfill in my needs as a pharmacy to provide me with my chronic medications. I complained to MedXpress that I don't get the service I require by way of not getting invoices from MedXpress for my co-payments and then be told that their system doesn't generate invoices. Furthermore the reordering system online doesn't work for me where I was without medication for 3 days due to the way it is set up to work on my cell phone as an app. I then decided to end my relationship with MedXpress for all medications and deal with Dischem directly. I have just in the past 10 minutes spoken to a lady from MedXpress in Durban and she told me that if I choose to get my Trivenz directly from Dischem then there will be a 20% service levy charged on my chronic medication called Trivenz. I find that totally unacceptable and just WRONG. Firstly we were FORCED to move over from Atripla to Trivenz due to a co-payment that Discovery would charge for staying with the Atripla so then we decided to move over to Trivenz in order to side step the levy/ co-payment. Now I hear that if I don't use MedXpress then I would STILL be subject to pay a 20%.