I cannot make in-app purchases - Clash of clans

I just bought a 25$ iTunes prepaid card, redeemed the card on my account all is good so far, then i open up my clash of clans game, and i click buy on a pack of gems for 19.99 and it keeps giving me this error.

"Your purchase could not be completed. Contact itunes store support to complete this transaction"

I have emailed them and still nothing, Anyone else have this issue?

Thanks,
Brandon.