I made one of the original posts on this forum about the issue. After MONTHS of verizon and apple passing the buck, it's FINALLY fixed, though not through either of their help, but by coincidence.
Seeing the post from 3 days ago about a carrier update, I went to settings, then general, then about. Next to cellular, it said extended. Tap that, and a notification will prompt you to download a carrier update. BOOM back on verizon.
FYI I have an iPhone 5c with iOS 8.3. I had terrible battery life on extended... Hoping this fixes it. Unfortunately my battery percentage has gone down 3 percent while writing this. Maybe it will adjust? Or maybe Verizon's incompetence has resulted in a ruined phone? terrible all around no matter what