How does China Mobile inquire about the validity period?

Description of validity period of mobile customer's balance: 1, GSM, M-Zone, Bank of China (customers with non-zero monthly rental card or original zero monthly rental card have successfully applied to cancel the validity period of the balance). As long as basic account has enough balance to deduct expenses, it can be used normally. There is no limit on the validity period, and there is no inquiry about the validity period. 2. The validity period of the original zero-month lease card customer refers to the period when the mobile phone number can be used normally. If you don't actively send "QXLYZYXQ" to 10086 to make changes, the current validity rules will remain unchanged.