Each country controls access to the cellular network. That has to happen first. In the US, the relevant bodies have not authorized access yet - so the dongle doesn't work there - same in Canada here. Once that's OK, you will still need to get...
You hit something...or perhaps lost a prop. That Drone didn't just fall out of the sky.
If you believe DJI's decision was incorrect, you can try to appeal the denial by providing additional information.
Gather all your documentation. Collect...
Here's a link to the list showing the countries where the dongles can be used for 4G transmission. Yes - I see that Australia is not on the list - but perhaps the list is out of date? You can also contact DJI and ask them about which country(s)...