If you claimed a gift card previously and need to have it resent, you can download your gift card history. To do this, first login and go to the "Rewards" tab. Scroll to the very bottom of the page and find the "Email Gift Card History" button. Click this and you'll be emailed a file that contains all previously claimed gift card codes and when they were claimed. You can then use these codes on Amazon.com as long as you have not previously claimed them.