The final status will not be the refund status "REFUND_FAILED".
* Supplement When you accept the Refund a payment API, the refund status will be "CREATED".
After that, the refund process is performed by the asynchronous batch process inside PayPay, but this process keeps retrying until the refund is successful.
Therefore, in the end, the refund status will always be "REFUNDED". It can occur as a temporary status during processing.