Hello,
I no understand why Australia Post make them pay to fix problem
If you have a problem using the Australia Post's API, then you should only contact the Australia Post support, but they WON'T charge you, but only advise you on how to fix your issue and that's the same on the Hikashop forum for the Hikashop extension.
I no understand why I need to pay to fix problem. That is why I look here to try and understand.
Probably because she took the time to check and debug it for you, but I also don't understand for what the Australia Post support charged her.