Iphone 4 can't be heard while calls in or out

[Bingcai47]

When making calls, or someone calls me, the other party can't hear me.(i can hear them). As i remember when this problem happens, the other party can hear me in first 10 seconds, but now these three days , it became worse and can't hear at all.i check the speaker is fine, i can record and play.
and i did some solutions like clean lints and restore , but can 't solve the problem.

Looking for help , thanks

 

[Bingcai47]

i went to the apple store and they checked it and told me that it maybe the hardware problem. option one i can be heard while i using the headset to call to receive calls. option 2, pay $149 to get a replacement. My warranty was passed 7 days. Damn it.
Hardware problem isn't caused by us, How to protect our rights while using apple phone.