Unfair return and refund policy

I bought wool from Metro Lifestyle Centurion on 9 June. I originally wanted baby wool for my project, but there were only 5 ***** available and I was concerned that it would not be enough for my project. I was assisted by a shop assistant and eventually bought 6 ***** of double knit. Once at home, I started on my project but soon realized that the double knit wool is not suitable. On 11 June I tried to exchange the 5 remaining ***** of wool which I had not used at all to Metro only to be told that they do not exchange wool and that it is on their refund policy at the bottom of my till slip. The shop assistant never advised me that wool cannot be returned and there is no signage visible in the shop to that extent. The manager, Carrim advised me that they adopted the policy because people remove the inside of the ***** of wool before returning it. I asked him to inspect and weigh the wool, but he refused to even look at it because he knew his argument was ridiculous. I ended up buying more wool from Metro without getting a refund. Regrettably, I only realized afterward that I could have bought wool from a sewing shop in the same mall. I am bitterly unhappy about the service and treatment I received.