Unfulfilled order & still waiting for refund

I placed an order for an expensive portfolio case on 5th June and the payment was taken out on 8th June. I was then emailed on the 8th (after the payment) that the chosen item was on 'low stock' and therefore not available, and that they can offer me one with a different colour. I responded saying 'please show an image of the other item so I can make a decision'. However, I was told that they did not have an image of the product. Anyhow, I then requested for a refund. This refund was requested on 8th June. It is now 16th June and I still have not had my refund. I am beyond disappointed with this company. Not only did they NOT advertise that the product was unavailable, but they ALSO TOOK MY PAYMENT without being able to deliver the product. I have since 8th June sent regular emails to request for my refund, and I also called on 12th June to speak on their customer service helpline. So far the only response I have received is 'I apologise, I'll follow up'. This is unacceptable. I am not sure how to get my refund???

The funny thing is, I can understand the stock is not available and I was understanding of that. Initially I also thought I will order again if the original item became available. Not anymore. It is not 8 days later and I am still waiting for my refund. Do not shop from this store. I am yet to see if I will get my refund. Very disappointed.