Returning an item

I wanted to return an item that was small in size and they did not have a large size. They refused to give me my refund so I can buy it some place else. The manager screemed at me and dismissed me. To stop the loud argument I ended up exchanging it with something that was R210 more expensive which according to her was "the store's policy"..and guess what? I still need the item that I wanted to buy initially. They did not have a size. What does our country's consumer regulations say about the return policy. How long will these retailers continue to bully us like this? I want my refund!