Cant hear when others call neither i can hear when i call but they can hear

Hello,the problem you are experiencing could be caused by two things,
1.Bad ear piece:this could be fixed by replacing the bad ear piece,you can get it fixed either by getting the ear piece parts from any phone accessories stores and fix it your self,or you visit a mobile phone engineer to fix it for you and your phone would work perfectly.
2.ear piece volume low:this could be fixed by dialling a number on your phone screen,then tap on the botton on the right side of your phone,ensure you tap the upper arrow to your desired volume level.
wish you good luck,
take care.