Apple Gift Cards cannot be redeemed at the iTunes Music Store.
Apple Gift Cards can be used to purchase an iTunes Gift Card (Plastic), but not an iTunes eGift Card.
Apple Gift Cards are issued by Apple Value Services, LLC
To report a lost or stolen Apple Gift Card, please contact Apple at any Apple Retail Store location or by telephone at 1-800-692-7753. Replacement cards will be issued after Apple verifies that the lost or stolen card has not been redeemed and you present your original purchase receipt. Apple is not responsible for lost or stolen gift cards.