Q: Can't make purchases with gift card with bad credit card on account

I recently had a problem with iTunes using my debit card.  Since I also had a bad magnetic stripe on the card, I had the bank issue me a new card.  The new card has the same number but a new security code.  iTunes still will not accept the card for some reason.  I called support and was told that it was a fraud protection issue with the card and I would need to speak to someone in billing, however, I was disconnected when they transferred me.  I rechecked my bank statement and there is no fraudulent activity.  Until I can call back, I purchased an iTunes gift card to buy an app.  I have the gift card credit on my account but when I try and buy the app it asks me to verify my card and it of course fails the verification.  I can't get past this to use the gift card instead of the debit card.  How can I bypass the debit card and use the gift card?