Try this link sir
http://www.satechhelp.co.za/8963/Hard-Reset-Mobicel-Vivo?show=8963#q8963
if the above method not works then you have to flash the phone the link is below
http://www.satechhelp.co.za/14365/Reload-Firmware-Rom-Mobicel-Vivo-Singel-Dual-Sim?show=14365#q14365
http://www.satechhelp.co.za/8963/Hard-Reset-Mobicel-Vivo?show=8963#q8963
if the above method not works then you have to flash the phone the link is below
http://www.satechhelp.co.za/14365/Reload-Firmware-Rom-Mobicel-Vivo-Singel-Dual-Sim?show=14365#q14365