To fix the phone, you will need to contact a friend, family member, or colleague with a windows or mac that has i tunes installed.
T hen, you will have to follow these steps.
Hold the Sleep/Wake up button to switch off the device until the slider comes up. Slide to switch off the device. You can also do this alternatively by holding Sleep/Wake button and the power button for a few seconds to switch off the phone.
Step 2: Connect the USB cable to iPhone but don’t connect it to computer. Launch iTunes.
Step 3: Press and hold the Home Button and connect the other end of the USB cable to the computer now (make sure iTunes is open at this time).
Step 4: Keep holding the Home button and wait for the device to switch on. After few minutes, the ‘Connect to iTunes’ will appear on the device. This is where you let go of the Home button.
Step 5: iTunes should say that the device has been detected in Recovery Mode. Select OK and Restore for the device to be restored.
With that being said, in the future try to be careful when the phone says its updating or downloading or installing anything apple related.. The phone has to have certain programs and updates to run properly and if you cancel or stop those updates, you almost always have to restore the phone using a computer and the itunes program on that computer.
Senior Technician and Network Switching Systems Operator / Maintainer.