Dishonest online store

I purchased HP Ink cartridges online, paid via credit card, received order confirmation. The order was cancelled 1 hour later because of the items were out of stock. But now they will only process my refund according to their refund policy within 7-14 days, leaving me out of money to purchase the items somewhere else. I phones the call centre - no help. Since they cancelled the order, they MUST process the refund immediately!!!