It is very likely that legal action will be taken against Optus...

It is very likely that legal action will be taken against Optus for the nation-wide internet outages that have caused financial losses at many businesses.
The reputational damage to Optus, however, may be greater - with many disgruntled customers likely to switch to TLS.

Reuters R. Hose 9.11.23 said

"Australia said on Thursday it would investigate an outage at telco Optus that cut off internet and phone connections to nearly half of its population, causing widespread chaos and leading some small business customers to seek compensation.

More than 10 million Australians, 40% of the population, were hit by the 12-hour network blackout at the nation's No. 2 telco firm for much of Wednesday, triggering fury and frustration among customers and raising concerns about the country's telecommunications infrastructure...

Other customers including cafe owners and niche online retailers told media outlets they would seek compensation for lost revenue.

"There's no doubt that it has to be on the table," Assistant Treasurer Stephen Jones told ABC Radio. "If you're a small business that's lost a day's takings because your phone system wasn't working then you're going to be asking those hard questions."...

The government would undertake a post-incident review into the outage that hit payments, transport and hospitals, Communications Minister Michelle Rowland said, describing the impacts as "particularly concerning."...

But UBS analysts said Optus now faces the possibility of losing customers to Telstra (TLS.AX), the nation's largest telco firm, and TPG Telecom (TPG.AX) due to "strong brand perceptions" of the network quality of rival".