Found a temporary solution for the "Phone" app,
- Go to settings - Apps - Manage apps - Find the Phone app or search it, then Clear all Data (Don't worry it will not remove your call history or contacts)
then restart the phone. try to call someone if it works for you.
for the messenger app, this is the only thing I did so they can hear me.
if you are the one calling, don't use video call right away, just use call and don't press loudspeaker if they didn't answer the call, they won't be able to hear you.
after they answer the call you can now use the videocall, the camera will popup twice I don't know why.
I hope this works for you.