Unicom just sent me this: Dear contract customer, as of the 20th of this month, it was detected that your mobile phone was separated from the user number card.

This may be because your mobile phone number has handled the preferential activities that need to be equipped with a calling card, but the calling card has been used alone during the contract period. After the system detects this situation, it will send you a short message to remind you. For example, during the contract period, the mobile phone number and the contract mobile phone must match the calling card to enjoy the terminal subsidy. During the contract period, the mobile phone is not bound with the mobile phone number card, which is regarded as a breach of contract. After the default, the mobile phone number card will stop and the iPhone will be locked. In order to avoid unnecessary downtime and mobile phone lock, it is recommended that you match the number with the contract mobile phone card as soon as possible.