I think I was scammed

Unfortunately, the One NZ logo/branding is often used by scammers, it's best you block this number if you can and make sure you don't hand over any personal details. One NZ would never ask for any kind of payment when it comes to a prize.

If you have given over any personal information or account details you will need to contact your bank to secure your information.  From here you should report the attempted scam to Netsafe.