I posted this in another thread similar to this and hope this may be useful to some. There is a problem and there is a partial workaround while they fix it. Please contact iTunes by email in order to have your accounts unblocked.
"This is definitely a system glitch from Apple iTunes that was happening to fewer people last year and intensified this last couple of weeks to a lot of people. It is not a geo location problem, but some issue with the application store anti-piracy system or whatever security feature on iTunes that became rogue.
The offending computer or device used with the account when attempting to purchase an application, becomes blocked (or embargoed) with the credit card declined loop were it is not a problem with the card, as any other payment type are also blocked, including the "none" option.
There is no need for people to VPN as the problem is also happening to US accounts based in the US, like mine.
The workaround is logging to the iTunes account in a computer different from the one that "caused" the glitch and filling up the remaining information when asked to verify the account. Still did not verify if this works under iTunes 10, but all different computers under version 9 I tried worked. However they became blocked again when tried to purchase an app. It has to be done with a computer that did not try to purchase apps after the first computer was blocked.
The embargo will continue on the app store and the user will be able only to update applications, download free applications, buy movies and songs or whatever. Don´t try to purchase apps or your computer will become blocked again.
This will work on all devices linked to one´s iTunes account, including Apple TV, PCs, iPhones and iPads.
This will work until a supervisor at iTunes unblocks your computers and account. They are overburdened with the launch of the new ipods and new iTunes 10. In my case still waiting for more than a week exchanging messages with an extremely polite agent that can´t do this by herself. iTunes does not have a customer service desk reachable by phone, only email. So hold on to your seats.
When attempting to purchase an application, the in use device or computer will become blocked and the verify account information loop will come back. Then the fix has to be find another computer (not used before) and start all over again. This works like a virus that spreads after the first device is infected as the account becomes infected. Only a non infected computer can be used for the workaround.
I am sure Apple, as a great company they are, will fix this on due time and when they recognize the problem(maybe they already have), but until then this is what is presented. "
