What is the automatic deletion of mobile customer service SMS?

This may be set in your mobile phone, for example, when the number of saved short messages reaches a certain value, it will automatically clean up the short messages. In addition, you may have set up another function of your mobile phone, which is to automatically delete some spam messages (or some fixed number messages) after reading them.

Short messages are generally not deleted by other people or organizations. Don't worry. It's basically a matter of setting up your own machine.