Mic issues after screen replacement? iPhone 7

I had a fairly minor crack in my screen, but the LCD was also broken. I took it to a local phone repair shop and had the screen replaced however, the microphone is now broken. I took it back to the store and they said there is no way they couldve damaged it because they simply did a screen replacement.

My question is: is it possible they did damage it during the screen replacement and now want me to pay more to have the microphone fixed or is it fairly unlikely... I don't particularly trust them.
Thanks