CHARGING ME FOR ITEMS OUT OF STOCK!

This is not the first time that this has happend, and its the third time I msged the help center and got no response. I have been using sixty60 for years now, onky now I realised that after I make a purchase the money goes out of my acc but when there's an item out of stock the invoice amount decreases but I don't get a refund and the initial amount is what is taken out of my account. I have queried in case I am mistaken but the amount deducted from my bank is the same as initial amount and once an item is out of stock I don't get that refund.