Problem in buying coins

I bought an itunes gift card and redeem it using a US apple account in my ipad. And when i press the buy coins, it showed a sentence like this "your purchase could not be completed" that dissapoints me. Please help me with these problem.

Have you updated your appleid security questions in the last year?
Also it almost sounds like either wrong password, Or the gift card hasnt registered with apple. i would check your Appleid to be sure.

1 more thing, edit your payment, If you had a credit card before take it off by selecting payment "none".

Did you buy the card in the US?

Hope this helps, U can buy me some too! Kidding

I recently created a US Apple account and choose "none" in payment and and it is required to redeem a us itunes gift card using that account. So do i have to update the security question, also, i finished the Two Step Verification System. I bought the gift card in a gaming boutique here in Philippines called Data Blitz. So how can you check if the gift card is not registered?

well u can check your appleid, it should sow your balance if the card was good and is credited to you. If not you have to go to apple support. can go here:
http://support.apple.com/kb/ts1292

I would check balance first.