Shop closes earlier than it should at 17:45

I went to Mr Price Home in Tsakane mall (in fact I'm still there now) and I found the shop closed at 17:47. I had bought an item that I needed to return urgently because the size was incorrect. I had already bought the correct item and so I urgently needed the refund. To think I knocked off early today just so I could rush to Tsakane mall and get this refund. Waste of petrol waste of time and I'm still without that much needed refund. I didn't get the name of the cashier as she stood at the till when she rep**** as I peaked through the glass door that was barricaded but I'm highly disappointed at Mr Price home and I really feel that they've put me in a negative position just due to being lazy to keep the store open for another 15min as per what is stipulated in the store's operating times. The cashier also had the nerve to lie to me and sat they close at 17:45 when I asked what time the store closes!