See 12.1(c)
"Nothing in these Terms is intended to limit any rights or remedies a User may have under the Fair Trading Act 1986 or the Consumer Guarantees Act 1993."
And 18.4(a)
"You agree to use our service in accordance with the law in New Zealand and the applicable law in your jurisdiction. Where any of these Terms does not meet the minimum requirement of the law, those terms and conditions are deemed to be amended to the extent of compliance."
Seems like boilerplate lawyer-speak to me: these are our terms, but some of them 'may' be overridden by law, and it's solely up to you (or perhaps the courts) to determine what is or isn't valid.
Regardless, I doubt that a company could legally limit their liability to repay funds held on behalf of customers. Otherwise, they could just close up shop and keep the difference.
The Acts mentioned are the standard consumer protection acts in New Zealand; those clauses are just saying they cannot contract out of the provisions provided by law (which for these laws in particular is correct)