How to query the validity period of Unicom mobile phone card by SMS?

Unicom's mobile phone card has no expiration date now, so it can be used all the time as long as there is no arrears. The 3G subscription is valid as follows:

Since May 2002 1.20 1, China Unicom has cancelled the validity period of all prepaid products with monthly rent or minimum consumption. Prepaid products that cancel the validity period of telephone charges still retain life cycle management such as recharge period and lock-up period. When the account balance is not enough to deduct the monthly subscription fee, it will enter a 90-day recharge period, and it must be recharged before it can continue to be used.

There is no expiration date for the post-3G users. As long as you continue to use your number, your package will be kept.