What if the customer balance is insufficient?

In this case, the checkout method is as follows:

1. The member's balance is insufficient. Users can give the membership card enough value first, and then check out.

2. If the balance of the customer's membership card is insufficient, you can first brush out the remaining money on the membership card and deduct it, and then make up the remaining money with cash. This is the checkout process of the payment method of membership card plus cash.