For a safe transaction, do not close the browser window, press the back or refresh buttons or disconnect until you get a message on your screen which states that the transaction is complete. To avoid being billed twice inadvertently, don't press any button more than once. Transactions may fail if the server of your credit card provider or bank is temporarily overloaded. If this occurs, you should retry the charging the card a few minutes later. You will receive a transaction confirmation by email.