DR'S ******* CONSULTATION

I went to Dr S Miller in Kemptonpark on the 07/12/2018 for a consultation, they told me that I need to pay R100 upfront which I didn't have a problem with and they will claim R200 from my medical aid as their consultation is R300. Weeks later I received an sms saying that I owe them R272.87, I phoned them immediately to find out why I am being charged this amount, they confirmed with me that the medical aid only paid R30 as my savings were finished but my question was why am I still being charged so much if their consultation is R300. They told me that the R300 is only to see the doctor for a script, the extras are the urine test and the gloves used on me which I don't understand why I am being charged extra for those because that should be included in the consultation amount and if one doesn't need a script then what? Is this a way for them to make extra money on the side?