Repaired phone, now nobody can hear in call and no speakerphone option

This Iphone 7 plus was “repaired” at a local shop, the battery and screen were replaced but ever since everytime she tries to use the phone she cannot hear anyone, they cannot hear her and speakerphone option is grayed out. I replaced the speaker after finding the other one was damaged but still no change. I also discovered several missing screws and a knick across one of the ribbons, From the looks of it it wouldnt be surprising to find the front facing camera ribbon has gotten damaged but this seems like a different issue to me.

the 1 pic is just showing the missing screws, this was the 1st thing i noticed when I opened the phone.

2nd pic is showing what Id guess is a screwdriver knick from slipping off one of the screws

and the last pic is just showing the damaged speaker I replaced.