In order to get help, you'd better explain the history of that phone and how the problem started.
Such as was it after a repair, a hard drop, after someone repaired something in it?
Then more details about the problem:
When you make a call, you can't hear anything if you put the phone to your ear?
- If yes, when you put the phone to your ear, does the screen stay on or does it turn black?
- Does your front cam work? If you record a selfie video, do you hear yourself?
- You can't hear anything, but do people hear you?
If you make the call using loud speaker / hands-free, can you hear people talking to you? Can you hear them?
Answer the above and I'll edit this answer and give you suggestions about what you can do.