A heads up for all Optus iphone mobile users (victims?)
After being on hold to Optus for the best part of an hour I managed to sort two issues out
1. When you send sms to more than one recipient Optus billing (and the iPhone) see it as MMS and charge $0.454 per recipient. This also means that it is not part of my 100 free sms messages. Optus are aware of the problem but will only fix it if you quote problem report 8253114. The only solution for now is to turn MMS off in your settings/messages. They say they are working on it.
2. When you subscribe to an add on "mobile as modem" pack the data is bundled together with your plan data. So the usage is agregated, even though it appears as a separate item on your usage report, and on my iPhone usage app. Very confusing
Check you bills people, or you may pay for something you have not used.
Gruntled