Can't make calls after update

[Eddykwok]

I recently updated my Xperia Z2 firmware to 23.5.a.0.575.

After the update, my phone cannot make voice calls or receive voice calls! The call ends immediately after number is dialed.

How do I repair this? ( please give an actual solution and not just 'restore factory settings') And how can I ask a refund from Sony if it cannot be repaired?

[Uliwooly]

@Eddykwok

Things to try

restart the phone 

repair the phone with XC 

test a different SIM card 

keep in mind that this is a user based forum, if you still can't make calls, contact your Local support