How to inquire the balance of Unicom prepaid card

Users need to query the card purchase record. They can open the online business hall of China Unicom, click "Payment" > "Pay the phone bill" > "Query the online payment/card purchase record", enter the verification code obtained from the mobile phone mailbox filled in when purchasing the card at that time, and query the card purchase records of the online business hall and the mobile phone business hall in recent three months.