Even though Kogan Mobile is using the Vodafone New Zealand Limited network, Kogan Mobile SIM cards will not work on handsets that are locked to the Vodafone network or any other network locked handsets.
These handsets are sold cheaper normally as they are network locked - meaning it will only work with that company/provider’s SIM card.
Please contact the retailer or provider who you bought the handset from as they normally can provide an unblocking code, however there may be a fee involved.