Aussie Broadband has been fined for potentially putting the safety of thousands of customers at risk during a crisis.
The customers wouldn't have received emergency alerts on their phones between November 2021 and May 2022 because the provider did not hand over 30,000 customer records to a database.
The information is used by law enforcement and emergency services during disasters like bushfires and floods.
The company has paid a fine of more than $213,000 for "large scale" breaches of public safety rules.
The Australian Communications and Media Authority said Triple Zero would not have been able to locate the customers and they would not have received alerts.
ACMA chair Nerida O'Loughlin said she was not aware of anyone being harmed, but the company potentially put its customers at risk.
"It is alarming that Aussie Broadband did not have effective processes in place to identify that its customer information was not being provided for over six months," Ms O'Loughlin said.
"While the breaches should not have occurred, we are pleased to see Aussie Broadband moved quickly to upload the missing data once it was brought to its attention and has taken steps to comply in future."
Aussie Broadband said customer information was not handed over due to an issue with its reporting software, which has now been fixed.
"We are deeply sorry that this software failure went undetected leading to inaccurate records," managing director Phillip Britt said.
"Whilst we had several checks and balances in place, these did not go far enough and I'm confident that our new compliance checks will ensure this never happens again."
All telcos are required to hand over customer details to the database.
Over the past five years, 30 companies have paid more than $4 million in penalties for failing to do so.