Australia’s telecoms authority gave Telstra a slap on the wrist after finding it overcharged nearly 10,500 customers AUD2.43 million ($1.7 million) over a 12-year period.

The Australian Communications and Media Authority (ACMA) ordered the operator to comply with billing accuracy obligations detailed in the country’s telecoms consumer protections code.

An investigation found the company overcharged subscribers an average of AUD231 each between February 2008 and February 2020 for interim mobile service offered when customers’ landlines were being repaired or they faced delays starting a connection.

In a statement, ACMA chair Nerida O’Loughlin said the errors were a clear breach of the code: the authority warned further non-compliance could lead to penalties of up to AUD250,000.

Telstra reported the issue itself, telling ACMA the billing error resulted from mistakes made when introducing a new customer relationship management system in 2008.

O’Loughlin said to allow this issue to go unnoticed for such a long time and impact so many customers is “simply unacceptable”.

“Overcharging can potentially lead to financial difficulties for affected customers, which is why the ACMA considers accuracy in billing practices to be an important consumer protection.”

“If telcos are relying on IT systems to meet their regulatory obligations then they must have appropriate testing and assurance processes in place to ensure compliance,” she said.

The ACMA noted Telstra moved reasonably quickly to fix the problem and address the issue, including by refunding customers.