Welcome to the forum! Can you get into the phone at all? If so, Go into system settings, applications, applications manager, scroll down to mobicontrol and click on it. Clear cache, clear data, force stop, then uninstall.
If you can't get into the phone, you'll need to contact the person who sold you the device ave have them give you the password. (Hopefully it isn't stolen, otherwise you'll be out of luck)
Good luck & let us know how it goes.