Online orders. Customers at losing end!

Online orders are accepted, accounts debited only to be informed that they are out of stock and a refund will be made in 3 to 5 days. This results in the customer being unable to purchase anywhere else as Game has their money. They should not be able to cancel orders where funds have been paid. The onus should be on them to procure more stock at their expense if their online system accepts orders whilst stock is no longer available