Your credit/debit card has not been charged twice.
However, your financial institution may show a pending amount-(the amount authorized) on your credit/debit card statement in addition to the charge we made. The pending amount will typically, within two - ten days, drop off according to your institution's policy. This will look like two charges until the pending charges drops off.
During the credit approval/confirmation process, your credit card is not charged for your order. The pending transaction that you see is actually a pre-authorization charge done by your bank or credit card company.
The final and only charge, where we will take the funds from your credit card, will happen once the item has shipped.