Open the Phone app
Tap Voicemail
Delete any saved voicemail messages
Contact your carrier to disable voicemail service
Ask your carrier to turn off voicemail or set calls to ring longer
Turn off Call Forwarding if it is sending calls to voicemail
Go to Settings
Tap Phone
Tap Call Forwarding
Turn Call Forwarding off
Set Do Not Disturb or Focus to allow calls if needed
Use Silence Unknown Callers if you want fewer voicemail messages
Contact Apple Support if voicemail settings are not working