Energy provider AGL continued to charge hundreds of former customers for gas and electricity even after they had disconnected their services, a judge has found.
The Australian Energy Regulator took AGL to the Federal Court, claiming it contravened national rules by overcharging customers between December 2016 and November 2021
Justice Kylie Downes on Friday found the contraventions were made out.
The affected customers were Centrelink recipients who had Centrepay set up, meaning Services Australia automatically paid part of their welfare payments directly to AGL for their energy bills.
The court found even after the customers disconnected their AGL service, the energy provider continued to receive the Centrepay deductions and processed them as payments.
Services Australia contacted AGL in June 2013 to say it had become aware of the issue and that it considered the conduct was a serious non-compliance.
The energy provider responded in October of that year to advise it had reviewed its Centrepay processes and made a number of changes, including manual reporting.
The manual reporting was in place until January 2016 when it ceased for an unexplained reason.
In October 2019, an AGL employee identified there were customers in the Centrepay payment channel with high credit balances.
But the credit issues were not addressed until the middle of 2020.
In total, 483 customers using the Centrepay service were overcharged after they had cancelled their gas or electricity connection.
Justice Downes found AGL was aware of the overcharges and they had contravened sections of the National Energy Retail Rules and the National Energy Retail Law.
The judge ordered the parties to discuss appropriate orders ahead of a September case management hearing.
An AGL spokeswoman said the energy company was considering the judgment.
"AGL received no benefit from these overpayments and all those impacted have been refunded," the statement to AAP read.
