After the short message is sent, it is displayed as an empty number.

This number is used by mobile to send short messages to enterprises, and it is useless for you to call back. It has no voice function. If you don't want to continue receiving, the direct way is to blacken. You can also reply "TD", "n" and "0000". Generally speaking, enterprise SMS platforms have this function. If you reply to the above, it will know that you don't want to receive text messages. (Of course, different SMS companies may set different responses. )