I just signed up to Telsra's M BYO tablet plan on the 12 month contract for $35
After clicking through the purchasing process online, the website added an extra special offer of 2gb of data on top of the 5, making it $35 a month for 12gb.
This wasn't advertised anywhere so might be a mistake.
Did you take a screenshot for evidence when the inevitable complaint needs to be made to the Telecommunications Industry Ombudsman?