Unable to Make or Receive Calls After an Update | iPhone

Hello,

I am unable to make or receive phone calls nor text messages after I tried updating my phone to the last version. If I go to Settings, Cellular, it says "An update is required to use cellular data on this iPhone." I already tried the instructions on the Learn More option, but it does not work. What should I do next?

I will greatly appreciate your help!

For the data symbol (LTE or 5G since I have a 12 Pro Max) on the top right hand corner next to the WiFi symbol, I only see four short lines moving from left to right, like in an intermittent mode.

Thank you!