For Samsung phones, once every other method has failed, you may recover your phone by wiping everything off and start over from scratch with a factory reset (hard reset). Using this method WILL ERASE ALL DATA ON THE PHONE, INCLUDING PHOTOS, MESSAGES, ACCOUNTS AND CONFIGURATIONS.
Just press and hold these keys: vol up + home key + power button
until you see the samsung (or galaxy + model number) and release all buttons. navigate through with vol up/vol down to “Factory reboot ( /reset/restore) “ and select with “power button”; click on “yes” to perform a factory reset.
Leave your phone to it and when it finishes, will be clean as new.