The ACCC doesn't take kindly to ISPs offering "unlimited" deals and not explaining the details. The regulator has already won one battle with Optus over that kind of behaviour, and now it has launched a similar investigation against TPG.
The ACCC has objected to advertisements from TPG which claim unlimited ADSL2+ broadband is available for $29.99, since that price only applies when you also rent a phone line from TPG. As well, there are additional setup charges not included in advertising. We noted this plan (at the full price) at launch and it's still a relatively competitive deal, but the case highlights the importance of checking all details before you sign up.