If you register for the one-month-free campaign using a debit card, prepaid card, or non-Japanese card, due to the way these cards are processed, you may be temporarily billed the fee for your selected plan (monthly, 3-month, 6-month, or 12-month).
You can rest assured that the amount will be refunded through your card issuer.
You may also refer to the Help article below for more information.