The back light of my UMI PLUS E phone never worked, so, nor the flash of the camera, and neither the lintern light work . It happens from the beginning. Any sugestion?
If didn't work from first day I can suspecting lose contact (hardware). You can contact seller with full explanation or open phone. Of course this will void warranty.
Also before that you can try perform factory reset (settings - backup and reset - factory data reset) and check for updates (settings - about phone - wireless update)