I can hear other people but they cant hear me

If you can hear and you can't hear others, then it's clear that the problem is with the Microphone, you'll need to replace it or you'll need to get it repaired. Not just the mic, it's also possible that there's problem with circuit which interrupts the functionality of mic. This won't be a problem that you can do it yourself if you are not familiar with mobile repairing. You'll need to visit a service center or a mobile repair shop and get it fixed.

Let me know if you need further help.

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