I'd suggest to navigate to your network providers support pages and there will be some advice on how to disable your voicemail.
It's usually via dialing a specific shortcode into your phone's dialer and or call their customer services @stuart1048
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. "
