Representative not aware of store returns policy

I bought a bedside lamp in Menlyn on friday and had to return one of the lamps to the Kollonade branch. The cashier who was helping me called the supervisor Tumelo to assist her and authorize the return. He started by explaining that the packing procedure used in Menlyn was incorrect and proceeded to process the return. It turned out the lamp was discounted in Menlyn and was being sold at normal price in the Kollonade store. He informed me that I needed to cover the additional charge. I explained how that is against my rights as a consumer. We argued about this back and forth his final resort was to say I must return the item to the store where I had bought. My nearest store is Kollonade and I will return the item there. I am appalled by the guy's conduct as he should be well informed of store liability and Mr Price's returns policy. I would like this resolved as I won't follow the instructions of an ill informed store representative.