Don't sell what you don't have

I paid R3,600 to Makro online sales on 6th April (more than one month ago) for 2 cases of prosecco (24 per case). Makro have told me three times, they are sorry, they have no stock. I have asked for a refund TWICE. Apologies don't really cut it. I ordered them early in order to have them as thank you gifts at my birthday. How much interest have I lost with Makro sitting on my money instead of me?