Why do you still display your mobile phone number when you send a hands-free message with 139 mailbox?

Honey, are you sure you chose the "hands-free SMS" mode when sending SMS? Using the hands-free SMS sent by 139 mailbox, the message received by the other party can be directly displayed on the screen of his mobile phone. After reading, clicking Close will not automatically save the message, nor will it display the sender's mobile phone number, as shown below. If you use 139 mailbox to send hands-free SMS, if the SMS received by the other party shows the mobile phone number, you might as well send me your and the other party's mobile phone number, the sending time of hands-free SMS and the screenshot private message, and we will check it for you.