My card redemption code was scratched off

Try contacting iTunes Support (they are likely to want to see images of the front and back of the card and its receipt) : http://www.apple.com/support/itunes/ww  (click on your country's flag, the country where you live, and which is therefore the country on the account ; click on Contact Support towards the top right ; click on Get Help under 'Talk To Us’)

my gift card code was mistakenly scratched off