Interestingly the some of the sales material states "If a system is using more data than anticipated, Telstra Wireless M2M [Machine2Machine] Control Centre can alert you or automatically message directly to a device installed in the vehicle. Automated alerts and business rules monitor the health of the devices and instantly modify services based on exception activity." Guess Aurora weren't taking advantage of that.
http://www.telstra.com.au/mobile/browsing_packs.html#packs