UnionPay APP

Cannot use fingerprint to pay, and CS instructed me to re-install the app. But after reinstall, said my card cannot be used while I would like to recover my password....bad experience. So finally, I have no way to recover my account.....

Unusable app. It can't even verify users identity for the app to be functional

I use it to pay MTR fare. It just fail to deduct from my card without reason. After some time, it reported that my card is expired. But, my card on hand is NOT expired. Anyway, I bound the card again by scanning. It said that my card is already bound. So, this confirm that the already bound card is NOT expired. I try to un-bound / delete that already bound card, but there is NO way to do so. There is NO button to un-bound / remove the card from the app