Silent calls.

[Sazzle66]

I can make and receive calls but no sound. No sound of a phone ringing, no voices. Recipients cannot hear me either. WiFi calls still work, just normal network calls are dead. I have a feeling this is to do with my last update. Help please. 

[Star_girl]

When I received my S20U years ago I had the same problem with calls. I have done factory reset and everything was normal.

[Sazzle66]

Thanks. I've never done that before which means backing up all my stuff. That's gonna be a roller coaster ride.

[Star_girl]

Idk, that's what I've done, the phone was brand new from the box. Maybe Google or YouTube before you do factory reset. But you can back up all your data like you said so it should be alright.

[Sazzle66]

Update.
Turns out the latest software update 'killed' my sim card. Lovely people in my local 02 shop sorted me a new generation sim card. I'm back up and running.