This solution will help only if you have access to the phone with iTunes or have previously backed up the iPhone to your computer. If possible, do a backup of all of the data on your phone. Then head over to iCloud.com, go to Find my iPhone, and hit erase phone. This will do a restore of the phone without requiring you to do anything on the phone itself. Within seconds you will see the apple logo appear and the device will boot. Then, connect to iTunes, restore from backup, and the phone should be right where you left it. Worked for me with the same issue and hope it can help someone else!