Mic not working after iOS 14 update

So I run a small repair shop, and I sold a phone too a customer

I tested the phone before the sale, and everything worked perfect

Now the customer came back with a weird problem.

They updated the phone too IOS 14 and the mic stopped working, but only during calls

I can record a video, use snapchat, record a memo and so on

But it just won't work during calls, I tried installing a new “Charger Dock” but still no luck during calls

I am really at a loss here, because it seems like I owe the customer a new phone…

I already tried turning “Noise reduction during g calls” off, but with no luck. I also tried factory reset both network and the entire phone…

Best regards Jonas

Mac-Shack

Holbaek, Denmark