iPhone 7 ios 15 microphone and speaker does not work sometimes
After upgrade to ios 15 sometimes mic and speaker does not work in phone app, camera etc
iPhone 7
Question marked as
First try a Forced restart
https://support.apple.com/guide/iphone/force-restart-iphone-iph8903c3ee6/ios
If no better
You should arrange a repair
https://support.apple.com/iphone/repair/service
Anything other than Screen or Battery may be a replacement phone and the price is in the article.
You can see additional service information within the following article:
Prepare your iPhone for packing and shipping