Update 10:00 am EDT: The maintenance is over. All functions of the account center are available again.
We will bring down the Account Center for a short maintenance tomorrow, Wednesday March 20th, at 5am EDT (10:00 CET). During the maintenance you will not be able to change subscription, redeem game codes or transfer characters.
At the moment we anticipate the Account Center to be back online at 10:00am EDT (15:00 CET).