Usually what happens, is while going through the order process it started a second order for you. You completed the second order, but your first order failed. The best way to double check this is to go to Order History and view your order history. You must be logged into your account to be able to view your order history.
Access Order History When Not Logged In:
Look in the top left corner of the site and click on "Sign In or Create Account" and login to your account. Once you are logged into your account click "My Account" in the top left corner of the site. Then you will look for the Order History link on the right side of the page. When you click on the Order History link it will list all of your failed and completed orders.