When I try to call and receive I cannot hear voice

when i try to call n receive i cannot hear voice.i can use all the apps n hear the voice.wen i try to use earphone cannot hear voice.wen i updated phone i was able to use for 5 to 7 calls normally for 2 hours after that same problem. so i want to know it is software problem or some parts problem

[Re-Titled by Moderator]