Ursprünglicher Beitrag von: Talon ,
Sounds like a base-level issue with the software. Have you used a computer to reset the settings and software, or only by selecting that option in the phone settings? I would recommend following [guide|52826|this guide] on iFixit to put your phone in DFU mode, and then using your computer to install a fresh copy of the firmware from the bottom up. That would be the most likely fix.