Okay tried I tried Resetting the Network Settings as suggested by some folks on the web.
settings >> general >> reset >> Reset Network Settings
That didn't work.
Tried resetting my voicemail password a couple more times. Nada.
Tried turning my voicemail password On/Off/On/Off/On/Off/On. Nope that didn't work.
Tried calling my iphone and leaving new voicemails. 7 times and not a damn thing changes.
There should be a GD option in the Settings to Enable/Disable Visual Voicemail. Then it should send some communication code to the Carrier that you wish to use Visual Voicemail.
Seriously this is garbage that I have to mess around until I wind up on the magical setting that triggers my phone to go back to Visual Voicemail.