Added static IP to my iPhone 5 and lost visual voice mail

I added a static IP to my iPhone 5 using the iPhone configuration utility and lost my visual voicemail feature. I can still get voicemails but I don't get notified when I have a new one and have to manually dial in the check. I've gone back and forth with both Apple and Verizon and both have told me it's the other's issue. In my latest convo with Verizon they told me this is a known issue that is specific to iPhones with a static IP attached or on a private network. They mentioned that the app store and verizon navigator don't work in these situations as well but they both work just fine for me. It's only the visual voicemail that stopped for me. Anyone have any insight into this? Is there a fix?