When calling or receiving on iPhone 5S, I can hear the caller, but the caller cannot hear me.
Can hear calls, but cannot talk. Caller cannot hear me.
I was totally stupid when I got my iPhone 5 and didn't realise it had a plastic film over the screen and ear piece. I took it to the phone shop and they peeled it off and laughed at me.
I am not saying you are that stupid like me but I did it and I know it has caught out others.
Good luck.