As a process of elimination can you try your sim card in another phone and then see if calls etc return to normal @Gavlar64
If they don't then it's your sim card or network connection.
If they do then as your probably out of any cooling off period you'd need to let a Samsung Experience Store or Samsung Service Centre run a diagnostic test on the phone.
Daily Driver > Samsung Galaxy s²² Ultra 256Gb in Phantom Black.
The advice I offer is my own and does not represent Samsung’s position.
I'm here to help. " This is the way. "