Do not buy online from Builders Warehouse

I bought a garden shed online from the Tableview branch on 18 July 2021 and was contacted the next day to inform me that the 2 units on the system were not in stock. I asked to be refunded and still haven't received my money back. I have phoned on numerous occasions and nobody has been able to tell me what they're doing about it. I've been told to wait 5 to 7 workdays twice. It's 18 workdays later and no money or feedback. This is unacceptable! All they keep telling me is that I have been refunded. I thought buying online from a reputable company like Builders Warehouse would be safe but it is obviously not.