The Australian Competition and Consumer Commission filed the case against TPG last week and sought to have the case fast-tracked in the Federal Court in Victoria.
It alleged TPG had engaged in "false and misleading" conduct because the $29.99 plan actually cost $59.99 a month when factoring in a compulsory home line service.
And it sought "injunctions, pecuniary penalties, corrective advertising and costs" from TPG.
But Justice Donnell Ryan refused to grant the interlocutory injunction against the advertisements, concluding that he did "not regard the ACCC's case for final relief on the present state of the evidence, as a strong one", according to representatives of the ISP.
TPG's sales and marketing general manager Craig Levy said the ISP was "pleased with the outcome".
"Thousands of consumers are today enjoying TPG's great value internet and phone services," he said.
"We will continue to fairly bring these and other services to the attention of consumers into the future."