It might be based on payment method - if your payment method declines SE drawing on the fees (ala, a credit card/debit card), particularly during a continuous 'reoccuring' subscription, SE will immediately suspend your account. You have to sort out the issue with the card issuer/bank first so that the card is registered as 'valid' and then re-register it as your payment method on the Mogstation/SE Account Management System. Once that's done you should be able to reactivate your account.