There are some incredible online training on Service-IQ which is an NZQA training provider for those in retail. If you have a look around the site there are everything from short online courses to those that build to accreditation.
Check them out:
The other business to contact is RedSeed https://www.redseed.com/ they curate (and incredibly cost-effectively), courses on all retail skills and are used by many businesses in retail throughout NZ. Ass they have developed the content you can talk about what may work for you – and then you have training to continue with your team for the future to onboard new team members.
Make sure you also check out MBIE to see if you are eligible for a training subsidy. While there are many free courses, the ones above can be as little as $25 per person, so it is worth taking the time to look at options. You can register and find out more information here https://www.regionalbusinesspartners.co.nz/