contact itunes store support to complete this transaction

Hi dear stuff,

I upload my iPhone 4's system to 6.1.2 and I down load the game subway surfer, I can not buy the coins in the coin shop, it told me 'your purchase could not be completed - Contact iTunes Store Support to complete this transaction.' I already top up my itunes account in the apple store today and I already finish all of my visa information at the time I register this itunes account. Please help me to solve this problem.

Thank you for your time.

Best regards.