Unable to make or receive calls on iPhone 12 after iOS 26 update

Hello,

after updating iOS on my iPhone 12 I am experiencing serious issues with calls. Mobile internet and SMS are working, but I cannot make or receive any phone calls. I have already restarted the device, reset network settings, reinserted the SIM, and checked both VoLTE and Wi-Fi Calling settings, but the issue still persists. Please check the configuration of my SIM card and the availability of voice services on the network side.

What else can I do to fix this issue? I urgently need my phone for work, and this problem is seriously affecting me.

[Re-Titled by Moderator]

Original Title: IOS26👎🏿