post https://komoju.com/api/v1/payments//refund_request
A "Refund Request" requests that a payment be refunded manually. This can be used for payment methods that do not support refunds, such as konbini. To support non-refundable payment methods, a bank account must be specified so that we know where to send the funds.
Since it is a manual process, the refund will be carried out at a later date, and there's a possibility of it being rejected.