Why is the balance inquiry rich and the SMS reminder balance insufficient?

According to the information provided by you, if the balance is displayed when you inquire about the phone bill, and the SMS prompts that the balance is insufficient, it does not rule out that the phone bill balance displayed in self-service channels such as mobile phone business hall or online business hall includes the phone bill items that have not been returned by your package, and the actual available balance of the account is insufficient. It is recommended that you contact the local Unicom artificial customer service to assist in the inquiry. The specific situation is subject to the data of the local Unicom system.