Unable to deliver product paid for

On 30/10/2017 I ordered a laptop (order no. ********** 36). The laptop was on sale for R14 999 (R8 000 discount). On 31/10/2017 I phoned them to confirm when delivery would be. They told me there was a problem on there side as there system didn't reflect the payment, but they had received it. I phoned nearly everyday since I made the purchase. On 03/11/2017 they assured me that the payment had finally reflected and that delivery would still take place within 5 to 10 working days from the 30/10/2017. When 10 days had lapsed and I had still not received the laptop I contacted them again and they told me that the laptop is in Four ways in Johannesburg and is still to be shipped. 14/11/2017 they phone me to say they are out of stock and will give me a refund, but are unable to purchase more stock from the supplier. I made the purchase first thing on 30/10/2017 the morning when the sale had just opened so unless they had a sale on a product they had no stock on then I expect them to deliver the product I was promised. They had also sent me sms's to say that my order was ready and I would be informed when it is out on delivery. So at some point they did have stock because they had two weeks and they could not inform me that they did not have any stock. I believe they sold the stock they did have and are now trying to get out of the deal. This is very unprofessional.