Voicemail unavailable.
Voicemail notices arrive and "red dot" the phone icon and will dial the voicemail system, but, no matter what 10-digit phone number I enter, the message replies "no such number". Additionally, under Settings, Phone, change voicemail password option is only reference to voicemail. It appears voicemail feature may have been removed, or disabled by some means. Please advise.
iPhone 6, iOS 12