Refinery exchange policy is not for customers

So I had bought 2 t-shirts from Refinery in Grahamstown on Saturday. When I got home I realized that I don't like the way both t-shirts fit me, so I went to exchange them on Monday and they told me they can't exchange the one t-shirt because it doesn't have a price tag even though they could see that it was still in its original state. I exchanged the one t-shirt but I mistakenly took the wrong size, so I go there to get the correct size and they tell me that they can't exchange that t-shirt for my correct size because their system does not allow that. What am I supposed to do with a t-shirt that doesn't fit me? On top of that they didn't want to give me a refund. Very poor service, I'm so annoyed.