unlocking bootloader in ZTE blade 7 lite

i installed all drivers and also extracted adb and fastboot in my system so i enter "adb reboot bootloader" code in cmd after changing into adb folder and then when i enter "fastboot oem unlock" it respond back "waiting for any device" but nothing happends then also what seems weird is my phone enters to "Meta Mode" and not "Fastboot mode" or something more relevant