I have also similar issue in iphone 7. After the new update i cannot hear any phone calls even there ringtone. Youtube is working fine. You can play music from library. Headset is not working. External bluetooth headset working fine during calls.
everything fine before the update. Phone has not dropped at all. There is no any physical damage from outside. Apple store said whole unit need to replace.
i have already restore to factory setting but still not work.
Please comment below is there any-cheap way to fix