Hi'
You have 2 option.
The 1st option will work only if your phone was linked with your Google account.
Enter a wrong password untill your phone request you to log in to your Google account. You will be able to reset your phone password after logging in to your google account.
Option 2 hard reset the phone to factory default' follow the instructions on the link below
http://www.satechhelp.co.za/2157/Reset-Mobicel-Retro-Factory-Default?