The reason why payment cannot be made by scanning Postal Pay with a credit card bound to WeChat is because the merchant does not support Postal Pay. Although many merchants on the market support WeChat payment, if the user pays the merchant by scanning the code, he or she can generally only use a debit card to pay, not a credit card. And if the merchant does not support Postal Payment, the user's WeChat payment Credit card scanning and postal payment cannot be used.