Whether you're using Prepay or a Pay Monthly plan, the My One NZ App really is the easiest way to manage your mobile plan.
You can use the app on your phone (whether it is Android or iOS), and you can use it online with a computer.

Learn out about using My One NZ on your phone.
Remember - you can even change your Prepay plan and your Add-Ons by using the My One NZ App.

You can also manage some services with just a TXT message, like checking your balance.