How can my iPhone network work back

I see you marked your post as Best Answer. People normally mark a post as Best Answer when it answers the question and no other replies are needed. If you mark a post as Best Answer when you are still looking for an answer, it may slow down any responses to your question. 

If you are still looking for a solution, please describe the problem in more detail. What do you mean when you say, “iPhone network work back?” We need the following information:

• Include the name of the device. Which iPhone do you have? What is its iOS or OS version?
• Offer as many details as possible about the problem. What were you doing or trying to do ? What happened? 
• Did your device show an error message? Did it include instructions? If so, what was the message and did you follow their directions? 

It seems English is not your first language. You can look for Apple Support in your native language in the link below.

Links for Apple International Support - Apple Community