its simple.its an old algorithm device...for anymore help post here back.
1.get imei and generate old algo code using universal code generator
2.download and istall dc-unlocker software
3.now detect modem by using the software.be sure your modem dashboard is not open.
4.if not detected select zte as default model.
5.then detect .
6.it will show your modem details.(dont forget you have to change the different simcard.don't use default)
7.now after the ====== lines type AT+CARDLOCK="your unlock code" hit enter
8.you will get "ok" as message.
tadaaaaaaa your device is unlocked.if any other problem post here back.