Problem with top microphone

Hi I have recently changed the on/off flex cable on a iphone 4.

After that everything works ok including the on/off button but now knowbody can hear me when on FaceTime or loudspeaker.

I believe it has a top microphone but pretty sure that came on the flex when I bought it.

If not can anybody give me information on where it is and is it possible that they don't come on the flex and I can purchase the microphone from you.

Thanks Shaun