Q: I can not regiter may itunes card

What happens when you try to redeem the card, and was it issued in the same country as your account is based (they are only valid in their country of issue) ? If you are getting a 'not activated' message then are you able to take it back to the store that you bought it from and ask them to redeem it properly ? If not, or if it's a different problem and this page doesn't help, then you will need to try contacting iTunes Support (you will probably need to give them images of the front and back of the card, and possibly its receipt) : http://www.apple.com/support/itunes/contact/ - click on Contact iTunes Store Support on the right-hand side of the page, then iTunes Cards And Codes