I've just upgraded to iOS 7 on an iPhone 4 and Visual Voicemail no longer works. Any Suggestions? Thanks.
You may find the troubleshooting steps in the article below helpful.
iPhone: Troubleshooting voicemail
Same thing happened to me....solved it by Clearing all deleted voicemails (took a while) then Disabling Siri then powering off and on again.....hope it works for you
Retrieving data ...