The $200 limit you're talking about there is only for our mPOS interface (https://pin.net.au/pos). This is configurable at our end, and happy to discuss with any merchant if they contact us at email@example.com.
If you're using the API (https://pin.net.au/docs/api), the per-transaction limit is set at $3000. But again, this is configurable on our end (we have a number of merchants who need this higher, for instance).
Don't hesitate to reach out if you have any other questions, our phone number is on our homepage if you'd like to chat.