Game manager refuses to refund for expired goods

I bought 12 boxes of kit kat chocolates at Game in Northam . Only to find out that 2 boxes had expired. I returned the 2 boxes and the receipt. The sales manager Emmanuel told me that their head office wants the expired chocolates also. These chocolates were for an event at a mine. How can I collect all expired chocolates? He was very rude. Iam being denied my refund. A well trusted brand sold me 2 expired boxes of chocolates and now refuses to refund me. They have lost a once loyal client