The Australian Competition and Consumer Commission (ACCC) has announced that only one quarter of the customers able to claim refunds from Optus for so-called "premium content" services such as ringtones, games, and horoscopes have done so.
Optus was forced to offer the refunds following a AU$10 million fine levelled at it in February from the Federal Court, after it admitted to misleading consumers and breaching the ASIC Act for its third-party billing practices.
Optus further admitted that it had knowledge from as early as April 2014 that customers were being billed for direct carrier billing services that they had unknowingly or mistakenly signed up for.
The Singaporean-owned telco made around AU$65.8 million out of commissions for the content since 2012, but no longer offers it.
"Optus committed to providing these refunds, and will continue to contact customers over the coming months," ACCC Commissioner Sarah Court said on Wednesday.
"Many of the affected customers were charged for content that they never wanted and never used, and from which they found difficult to unsubscribe. In some cases children unwittingly incurred charges."
The ACCC added that Optus and other third party providers had repaid AU$21 million to 240,000 customers prior to the latest instance.
Anyone wishing to receive a refund should call Optus on 133 937, the ACCC said.
The consumer watchdog alleges that Optus sent an email on 24 May 2018 advising some of its mobile customers that their broadband service would be "disconnected very soon" and encouraged them to "make the switch, before it's too late".
The email was allegedly sent to 138,988 of Optus' mobile customers.
Optus has since admitted it misled customers, apologised, and offered a free exit for those who accepted the deal.
"In October 2018, Optus committed to improving customer experience and customer service across our business and we continue to devote significant energy and resources to address issues like this and make the necessary changes and improvements so we can deliver great service to all our customers," Optus vice president of Regulatory and Public Affairs Andrew Sheridan said at the time.
According to the ACCC, between 2015 and 2016, Telstra made false or misleading representations to consumers by charging more than 100,000 customers for content subscription services who had not requested them or had the ability to opt out of them.