If your GFIVE President Tango 7 is stuck or frozen, You can perform a soft reset operation. Check out how to force restart Android 4.4 KitKat. As a result your GFIVE President Tango 7 should reboot and start running again.
At first, disable your phone.
Then you have to hold down the Power for a long time.
Very good! Your phone is successfully restarted!
At the very beginning, you have to open the back cover of your phone and remove the battery.
Then you should insert battery again and shut down the cover.
Press and hold down the Power to enable your phone.