wallet and secret code

hi guys i need to buy this game and this is my new ea accout and i need to put ea cash card i dont want to buy it with visa so i bought 2 usa gift card and i need to put them they have a secret code and i cant put it on product redeem code and my wallet isnt showing up the only payment method way is buy visa why? i dont have visa lol hope someone try to help me i did every single step on google and on ea help center and 0 help i got i still dont know where to put the secret code of the gift card to buy this game because the redeem code is 16 digit i got a gift ea card with 10 digits where shall i put this anyone can help me please ASAP