In order to protect the safety of both parties, UnionPay is not allowed to "wipe the account" after you swipe your card, and can only wait for the other party, that is, the payee, to return your money through a new transfer transaction. Avoided, the transaction is completed after swiping the card, and the other party's money is defrauded by wiping the account.

So, after you swipe your card, UnionPay will no longer judge whether your transaction is completed. The 15-day period is the "buffer period" and the business processing time for refund stipulated by Yongle in order to ensure its own transaction safety.