gift download was interrupted by internet disconnection

Hi all, I bought a friend of mine a book as a gift, she redeemed the code but while the book was downloading her internet connection was lost. when she wanted to re-download it again she couldn't because the code has already been redeemed but the book hasn't finished downloading. is there a way to fix this? or re-redeem the same code? or do i have to buy the gift book again?

thank you