The Federation of German Consumer Organisation has given Valve until October 10 to give a reasonable response to its desist order or face legal action.
The umbrella group of consumer rights agencies says the Steam EULA agreement, which requires consumers to waive thier right to class action lawsuits against Valve, is coercive.
Failure to consent to the new terms left several Steam users without access to their library of games.
The Verbraucherzentrale Bundesverband e.V., or VZBV, also seeks to bring Valve into compliance with the European Union's recent ruling on the resale of digital goods: a feature available only on Steam.
"Valve has a new deadline (10.10.2012) to respond to our letter now. Maybe after this time we will resolve the dispute in the court," the VZBV's Carola Elbrecht, chief officer and coordinator of advocacy for digital consumerism, told Cinemablend.
Valve had originally been handed a deadline of September 26.