(*) The order number is a unique reference. In case of repeating the payment process you have to introduce a slightly changed order number, f.e. xxxxx -2"(xxxxx is your order id) or xxxxx-02. If you should have a problem with the payment transaction, just use another credit card or contact the card issuer to solve the problem. You do not have to place a new order since the order process is not related with the payment transaction.