The Federal Court has ordered Optus to pay a $100 million fine over its sales tactics targeting hundreds of vulnerable customers, including First Nations Australians.
Optus had already agreed to pay the fine, after the Australian Competition and Consumer Commission brought the case based on tip-offs from financial counsellors.
Optus admitted its sales staff acted unconscionably when selling phones and contracts to more than 400 people at 16 stores nationwide between 2019 and 2023, including vulnerable customers such as Indigenous and intellectually disabled people.
Justice Patrick O'Sullivan described the company's conduct over several years until 2023 as "extremely serious" and "appalling".
"Senior management abrogated their management responsibilities and, consequently, Optus abrogated any semblance of responsible corporate behaviour," O'Sullivan said.
Optus chief blames human error for triple-zero disaster
Chief executive Stephen Rue outlined the causes of the 18 September outage at a press conference on Wednesday.
Rue blamed the issue on human error, brushing off concerns the company's Singapore owner, Singtel, had cut spending to Australia's second largest telco.
"Standard processes were not followed," Rue told reporters.
"That's not an investment issue, that's people not following process."
"That is a result of human error."
The first step of Optus' firewall upgrade was to divert calls to a separate part of the core network.
But preliminary investigations revealed this had not been followed.
The failure is the second time in two years a major Optus outage has prevented people accessing emergency services.
Calls for Rue's resignation grow
Pressure has continued to mount on Rue after revelations the company had not implemented a third of the recommendations that followed a review on its 2023 outage.
Rue took the reins in November after the earlier outage and a hacking incident that left millions of customers exposed to potential online fraud that forced the departure of Kelly Bayer Rosmarin as chief executive.
The Opposition and Greens called out federal communications minister Anika Wells for flying overseas in the middle of the current crisis, while urging Rue to resign.
Singtel Group defied the demands to sack Rue, a former NBN Co boss brought in to right the ship after scandals.
"Our hearts go out to the families and friends of those who have passed away and we know that Optus will get to the bottom of this matter," Singtel group chief executive Yuen Kuan Moon said in a statement.
"We will continue to fully support the Optus board and management team as they work through this incident and accelerate the changes needed."
Board chairman John Arthur also appeared to stand by Rue as Optus announced distinguished business woman Kerry Schott would lead an independent review on the outage.
Asked about calls for his resignation, Rue said the situation was not about him.

Kerry Schott most recently reviewed another outage debacle — on Sydney trains. Source: AAP / Bianca De Marchi
"There are no words that can express how sorry I am about the very sad loss of the lives of four people who could not reach emergency services in their time of need."
Schott's review will press for the causes of the outage and examine the operational management of triple-zero calls on the Optus network.
It will also look at Optus' response to the incident and whether it adhered to policies and legal requirements.