Ordered from an overseas website and the goods never arrived

You have realistic options. The Consumer Guarantees Act applies to overseas sellers only where they ordinarily carry on business in New Zealand, which can be arguable for a site that markets directly to New Zealanders. The Fair Trading Act 1986 can also reach overseas traders who mislead people in New Zealand, although enforcing it against a business with no local presence is hard in practice. Your most effective step is usually through your card provider. Ask your bank for a chargeback on the basis that goods paid for were not supplied, and do it promptly because card schemes set time limits. Keep screenshots of the website, the order confirmation and your emails. You can also report the site to the Commerce Commission or Consumer Protection so that the pattern can be tracked.