iphone ear speaker not working during calls

Try a Forced restart

https://support.apple.com/guide/iphone/force-restart-iphone-iph8903c3ee6/ios

If that does not work and you cannot use the vol up during a live call to improve it, as the phone is under warranty you would be better starting a Warranty repair.

https://support.apple.com/iphone/repair/service

If that does not help the  next procedure would be to backup then restore your device to factory, and setup the device without restoring a backup, to see if the issue is replicated. 

Then restore the backup.

If you need to send the phone in for repair or replacement then backing up and restoring to factory would be needed anyway.

Here is a guide for those steps

Backup and restore

(1)How to back up your iPhone, iPad, and iPod touch – Apple Support

(2) Restore your iPhone, iPad, or iPod to factory settings – Apple Support

(3) Restore your iPhone, iPad, or iPod touch from a backup

If that fails arrange a repair

https://support.apple.com/en-gb/iphone/repair/service

Force start didn't worked. Sim calls, whatsapp calls and all other audio or video calls are not working on my I phone 7 plus

please tell me