Send a text message to your mobile phone to check the phone bill and traffic balance. Why didn't you send a text message, and the mobile phone is not in arrears?

It may be a network problem. This is a two-way street. Maybe your message was sent, and the broadband resources of their server were not enough, so you gave up your message. It may also be that your mobile phone network is not stable enough, the message has not been delivered, or you can't accept the echo message.

Another problem is mobile phones. I had a mobile phone like this before, and I couldn't receive the phone bill information, but it's normal to change the card for another mobile phone.

If you think my answer has solved your doubts, please adopt it.