Help! How do you unlock Lg Viewty with the imei?

Im Vodafone and Really want to go onto 02.
I have a lg viewty phone and i have left the vodafone sim card in.
i then called 2945#*990#.
I selected sim unlock
But then i need a unlock code :/

Here is my imei code 354935029224549.
Could someone Please help ??