Hello.
This is the Gravity Co., Ltd. Ragnarok Online: Zero Operations Team.
We have confirmed an issue where G Cash charging via simple payment methods has been unavailable since the regular maintenance on October 6th, and we are currently investigating this matter.
Until a resolution is implemented, please use the other general payment methods that are currently available. We will provide updates on further progress through a separate notice.
We apologize for the inconvenience caused to your gameplay, and we will do our best to resolve this issue as quickly as possible.
Thank You.
Gravity Co., Ltd. Ragnarok Online: Zero Operations Team