RTFMing tells us:
https://secure.playonline.com/supportus/index.html (!empty($user->lang['WROTE'])) ? $user->lang['WROTE'] : ucwords(strtolower(str_replace('_', ' ', 'WROTE'))):
Credit and debit cards with Visa and Mastercard logos are accepted as the only payment method.
If you wish to change your current payment method, please
follow the steps below:
PlayOnline Main Menu => Service & Support => Membership
=> Payment Method => Register/Change
Anyway, I'd suggest you first search for information needed here:
https://secure.playonline.com/supportus/index.html
and here:
http://www.playonline.com/ff11us/index.shtml