Registration and change of credit card information usage for payment is accepted from the payment information page on the control panel.
Payment information page:
We use an authentication mechanism to check the validity of credit card. Repeatedly mistake entering credit card information may cause not accept credit card registration operations for a certain period of time. In that case, please wait for a while and retry to register your credit card information again.
Have you received a charge 50 yen (JPY) billing notice from your credit card company? The 50JPY billing you know may be a fake request created by the authentication mechanism. That 50JPY billing is fake, and will never actually be paid from your bank account.