In proceedings brought by the Australian Competition and Consumer Commission, the Federal Court ruled the energy giant engaged in unlawful conduct while negotiating electricity contracts with customers in Victoria, New South Wales, Queensland and South Australia.

Origin was ordered to pay $2 million in penalties and its marketing company SalesForce was fined $325,000 after the court found they had engaged in unconscionable conduct, undue harassment or coercion, and made false or misleading representations.

In one instance, a sales representative continued to negotiate with a consumer who was a native Tamil speaker after being told they had difficulty understanding English. The consumer was prompted to say "yes" when replying to questions on a phone call to confirm an electricity contract.

In another instance, a staff member kept negotiating with a customer after she told him she was not the authorised account holder. During a phone call to confirm a contract, the sales representative told the consumer to state that her husband, who was the account holder, had signed an agreement when this was not the case.

"In each case the sales representative practised deceptions on the consumers in order to secure their custom," Justice Anna Katzmann said. "They preyed on the vulnerable and the ill-informed."

"[The conduct] is serious, not only because of the deliberate deceptions and the exploitation of vulnerable consumers, but also because of the location and context in which the conduct occurred: at private homes to which the respondents were not invited."

Justice Katzmann also found that Origin and SalesForce breached consumer law by making false and misleading representations to a number of customers, including:  

• there was a mistake on the bill issued by their current electricity supplier;
• the consumer had to change to Origin because of government changes;
• the consumer would not be charged an exit fee if they switched to Origin;
• the sales representative was part of a government-commissioned study investigating complaints about energy costs; 
• the consumer was signing an expression of interest and would not change retailers unless they contacted Origin.   

The court also found the companies failed to leave the premises immediately on the request of the consumer, called outside permitted hours and failed to inform them in writing about their right to terminate a contract within the cooling-off period.

ACCC chairman Rod Sims said the fines were the highest penalties against an energy retailer and a marketing company in relation to illegal door-to-door behaviour.

"This reflects the serious nature of the contravening conduct, including the fact that Origin and SalesForce were held to have engaged in unconscionable conduct and undue harassment or coercion," he said.

"The message is clear – energy companies must ensure their sales representatives do not use illegal tactics when negotiating with consumers at their door."

An Origin spokesman said: "We're extremely disappointed that a number of customers had a poor experience, and while the conduct in question was performed by a third party on our behalf, it's our duty to ensure that anyone who represents us reflects our behaviours and values.

"We apologise to customers who were impacted by this behaviour."

The spokesman said Origin stopped residential door-to-door sales in September 2013.

The proceedings against Origin are the latest in a string of actions against energy retailers over inappropriate door-to-door marketing activities.

In April 2014, EnergyAustralia was ordered to pay $1.2 million in penalties. In May 2013, AGL Sales and AGL South Australia were ordered to pay total penalties of $1.555 million. In November 2013, Australian Power & Gas Ltd was ordered to pay $1.1 million in penalties.

Last week Energy Australia was fined $1.5 million after being caught duping householders into new electricity and gas contracts.