Voicemail unavailable

My voicemail feature is not responding to BELL. When my contacts call, they get a completely different voice greeting, not the one from BELL or my own personal greeting. If they leave a message, I don't receive it. Contacted the carrier and was told it's a software-related issue. Tried Force Start but didnt work. Tried to change the voicemail password in Settings- Phone but the feature is unavailable. Any ideas??