There is a in-game currency Black Gems (BG) used on servers.
When in the game click on the Black Gems image on the resource panel or on the number of BlackGem amount.
Choose
the payment method in the displayed dialog box:
The account activities and its state can be ckecked by clicking "Financial account" in the server selection screen
You can transfer the Black Gems from any server (where you have continuous subscription) to another one. For this purpose use the "Portal Purse": exchange the Black Gems from the server to ML$, and then from ML$ back to the Black Gems on another one.
Tou can always transfer ML$ from the Portal to the Black Gems on any server.
Common payment mistakes