iPhone 7 Mic doesn't work on calls - but works for voice notes etc.

Hi All,

My iPhone 7 mic works clearly for everything e.g. voice notes etc aside from phone calls.. When I make calls, the mic does not work clearly - people cannot hear me clearly on the other end and it’s getting frustrating.

Context: Took my phone to a guy who tried to replace charging port on iphone 7 because this charging port connection was loose (mic was working fine then on calls). He couldn’t do the job - b/c he said his replacement part was faulty.

Went to another place - Found out the previous $@$*!& repair guy threaded one of the screws - but new place thankfully replaced charging port correctly. This port also has a new mic. attached to it. Charging port works fine - mic is still same issue - which leads me to conclude, it’s probably not because of the mic now.

I’m guessing the previous $@$*!& guy messed something up. Any advice would be grateful - i don’t want to have to pay for a new phone if i can resolve this otherwise.

Thank you