Icloud memory iPhone

Make sure your iTunes billing information is correct.

Try purchasing from your Mac or Windows computer. If you do see an error, maybe it'll be a little easier to decipher.

iCloud: Purchasing iCloud Storage and Billing

Mac OS X    From the Apple () menu, choose System Preferences.    Click the iCloud icon.    Click Manage in the lower-right corner.    Click View Account in the lower-left corner.    Enter the password for your iCloud account, then click View Account and follow the prompts.Windows 7 and Vista    Click the Start Menu and go to Control Panel.    Go to Network and Internet.    Click the iCloud icon.    Click Manage in the lower-right corner.    Click View Account in the lower-left corner.    Enter the password for your iCloud account, then click View Account and follow the prompts.    Note: You cannot update your payment information or manage your storage from iCloud.com.