New Zealand Post

My client runs a store with this plugin in New Zealand, but she is losing money with people being dishonest or just wrong about their shipping needs (urban/rural).

I’m wondering if there is an add-on for New Zealand Post which the customer can input their post code or address and it gives them a price or shipping option?
We are looking for a solution for this plugin, as we have had no other problems, especially considering you were convenient in having Paystation supported with the Gold Cart plugin. We would rather a solution here than having to move to another plugin that does have support/add-ons for NZ Post.

Thanks

https://wordpress.org/plugins/wp-e-commerce/