Complaint for refinery at Mall of Mthatha

Yesterday I went to refinery mall of Mthatha,I purchased a pink dress. Did not fit it as I was in a hurry and did not try it on. Got home and only tried it on this morning. It was very loose, so I took it to the shop to down size it. I was denied due to that they said it had sweat stains. The dress was not checked prior only when I needed an exchange It was checked. I'm livid refinery please intervene. The dress costs R550 .