Bad customer service

My fiance bought a dress on the 15th December and as she tried to put it on at home the zip teared. Today 19th December we went to the shop so we can exchange it or get a refund. We arrive at the outlet at 7:45pm and the security lady was closing the shop, when we got to the till point the lady name Lebohang she was so rude and told me she can't help me because the outlet was closed. I couldn't understand why she's saying she can't help me because she's closed at the same time (1) I'm inside the shop at 7:45pm before 8pm which is the closing time, (2) they were other customers inside the shop who were still shopping. I felt so humiliated/emberrassed the way she spoke to me after I told her about the closing time as per the centre management agreement and the time she decided to close the outlet. I am so upset and irritated about the way this person treated me and I'll be very happy if Edcon deal with this matter accordingly, she let me leave the shop even thought she know she was wrong, the security guide she's my witness because she tried to stop me from leaving the shop unhappy and try to assist me with the right size.