Telstra took the decision to stop people on prepaid / upfront mobile plans from using premium sms. This means, this group of people cannot enter competitions like ‘Sunrise Cashcow’ and ‘7 Plus $50,000 Great Fuel Getaway’ etc. Nor can they choose to donate to charities via this method, nor can they vote in various talent / show competitions. Yet, Telstra still allows their Post Paid mobile customers to access premium SMS. 
This is clearly discrimination against a subset of their mobile customers who prefer a prepaid plan because it is more affordable. 
It also discriminatory against the less wealthy members of our society because it blocks them from potentially winning any of the available premium sms based competitions - leaving them for the more wealthy segments of our society who perhaps don’t even need the prizes they win.

When Telstra made the decision to scrap premium sms for their prepaid customers, they did not consult with them nor give them a choice as to whether they wished to continue the service or not.  When Prepaid Telsta mobile customers entered into their contracts, premium SMS was offered as an inducement to enter & stay on prepaid. At some stage, Telstra in their good wisdom decided to cut something out of the contract and just hope their customers did not notice or give a damn. Well, I think their prepaid customers have been galled by this action.