Can't make phone calls

Just updated my Pixel 7 pro and now I can't make or receive phone calls. I'm with Optus and live in Australia. As soon as I call a number, I just get "Call Ended." Done phone resets and service provider resets. YouTubed it extensively with nothing working. Google results show this be a common problem after updates. How is it acceptable that an update would destroy the primary function of the phone? I changed from Apple to Pixel for this reason. May as well go back. I expected better. Does anyone know a trick I might have missed?