No refund from Huntalot.com for out-of-stock items

I ordered (and paid for) goods from Huntalot.com on 4 September 2022. The next day I was informed that they don't have stock of the items I bought, so I asked for a refund. On 8 September I followed up, as the refund has not taken place yet. I was informed that it takes 3-5 days to complete a refund. It is now 11 days since I paid for the items and still no refund. Their system should not allow someone to pay for items that are out of stock, and they should have a much better system for dealing with refunds.