Where is this written?

I was told that if I want to purchase an Energy Drink and draw money from this Pick n Pay Express then they have to add R5 to the amount requested - ? And if I take just the cash on its own I asked - then it is still R5 that will be added to the requested amount. But how? Where is the written and how do you come on R5 and is it rise per amount you draw? Is this even legal because this is the only Pick n Pay I know of that does this. Or is it the Cashiers that are just pocketing the R5 as I have never heard of this before and this happens every time we go there.