DEBIT CREDIT CARD BUT NO STOCK

Order No: *** I have purchased a Gamo Big Cat 1250 Air Rifle + accessories online producing my credit card details. Received a mail the following day from Tian van Heerden that there is NO stock, & he requested further instruction - I rep**** back & told him to cancel the order. Although the order has been cancelled they debited my credit card. How on earth does this work? No stock but you take my money....