I am sorry robh to hear your news. its really sad! Qtel itself is warning about this in their website
http://www.qtel.com.qa/Mobile_Broadband.do
I have heard stories of non roaming usage by some people in earlier days with monthly bill running to 5K and all. You have to be very careful in using this mobile broadband. Disable all the automatic updates while online with that, use a good firewall with manual program control, disconnect when not needed, monitor your usage in your eqtel etc.