Forcing me to buy reusable bag

Why is Mr P Kenilworth centre forcing us to buy their reusable shopping bags at price of R5. Your cashier says we only using these bags and if you dont buy it you will be carrying your items in your hand. MrP promenade which I frequent and westgate mall gives us normal plastic bags and offers us if I want the reusable bag. Why are you forcing us to buy this bag??? Food *****s has a paper bag at a much cheaper price of R2 this is ******* and dont force me to buy your bag at a ridiculous price