Refund for a cancelled order not refunded

Order Number: ***, I placed an order for a Seagate Expansion 2.5 External Hard Drive-1TB and a DStv Next Generation Explora HD Decoder on the 22 December 2014, but however the Hard Drive was never delivered as it was out of stock, I sent an e-mail enquiring about the refund for R 799 on the 08 January 2015, and I was told it would take 5-7 working days to reflect, and I followed up again on the 20 January 2015 and I still have not received the refund.