the other person can hear you when you are talking on the phone, or the call is in complete silence?
If the other person can hear at least something or "far" means that the microphone is fine and does not need replacement. So, then problem is that when you replace the charging port & headphone jack flex cable you did not place the microphone in the right place, so is moving around and that why the other person can not hear you!
So just open the iphone and place the microphone correctly!