How long can I keep the missed messages on my mobile phone?

SMS messages are only kept for 48 hours, and then automatically cleared.

SMS will be stored in the system for 48 hours. If the phone is turned off or stopped, the system will keep the SMS for 48 hours. If it is turned on or receives a signal within 48 hours, it can receive short messages during this period. It expires after more than 48 hours, and you can't get it, and you can't get the text message back.

The mobile phone will only charge the sending mobile phone the short message fee after receiving the short message, and the short message that has not been received for more than 48 hours will not be charged.