personally, I think: 1. When selling the sales card: borrow: cash 3111; loan: advance payment 3111; 2. How to handle the customer's consumption time (1) When the consumption amount is 3611, Debit: advance payment of 3111 sales expenses of 611 loans: main business income of 3611 (2) when the consumption amount is greater than 3611 (if it is 3711), borrow: advance payment of 3111 sales expenses of 611 cash loans: main business income of 3711 (3) when the consumption amount is less than 3511 (if it is 3511), borrow: advance payment of 2911 sales expenses of 611.