you will have to erase/restore the device, have you tried?
Open iTunes on your computer
Connect the iOS device directly to a USB port on the computer
Turn off the iOS device (hold down the sleep/wake button on the top) until you see the red slider and slide the red slider across to the right OR until the device simply shuts off, if locked up.
Hold down the sleep/wake button (on the top) AND the home button (on the front) for 10 seconds
Release the sleep/wake button but CONTINUE to hold the home button, until...
iTunes should pop up and tell you it’s found a device in recovery mode, click ok and continue along for the restore