Telco goes public over scam calls it says flowed through rival network

Vodafone's owner has accused its rival, Aussie Broadband, of being involved as a carrier in almost all of the scam calls made to its customers in a one-year period.

It analysed millions of scam calls on the Vodafone network between July 2025 and July 2026 and found 98 per cent of the calls — more than 24 million — came via little-known internet phone company Symbio.

Symbio is owned by Aussie Broadband.

"Every time we see this type of scam campaign we give the evidence and the data to Aussie Broadband for them to investigate and block the bad actors,"  Vanessa Hicks, executive at Vodafone's parent company TPG Telecom, said.

"We want more urgent action to stop this activity closer to the source and stop these calls reaching Australians."

Symbio sells Australian phone numbers to companies in bulk, allowing them to make calls via the internet.

Aussie Broadband CEO Brian Maher said Symbio had about 500 customers on-selling those numbers. Each of those customers may on-sell numbers to thousands of other users.

He said because Symbio had no oversight over who its customers were selling the phone numbers to, stopping the scammers was very difficult.

"Where we find a persistent bad actor then we will disconnect them," Mr Maher said.

He said the company used detection software and a team of more than 20 people to reduce scam calls.

"We've got plans to invest further into the future and we'll continue to do that," Mr Maher said, but declined to say how many additional staff would be hired.

"It is unfortunate that they've called us out publicly, but we accept that they're frustrated and we want to work with them to solve the problem," he said.

Scammers posing as police officers

Perth-based Ian Odlum posted on Instagram last month about a strange call he received.

"I just received a call from someone saying they were from the Australian Federal Police," he said in the post.

Mr Odlum said the scammers sent him an email to "verify" they were from the AFP, before telling him they had seized an individual and their laptop, which had his personal information on it.

The caller told him he needed to come to Narrogin Police Station, around 200 kilometres from Perth.

"It was a very calm, very kind person explaining that they weren't going to ask for my information, but that they needed to speak to me and it was very important," he said.

Mr Odlum refused to travel to Narrogin and the caller hung up.

"I don't know exactly what he would have gotten out of this, but it's really scary how real this scam feels," he said.

Vodafone's fraud team investigated and found police stations in Western Australia, Queensland, South Australia and the AFP had all been impersonated by calls from Symbio's network.

"What we've seen in this particular scam is over 2,400 calls, and this was just in a one-week period in September," Ms Hicks said.

The regulator, the Australian Communications and Media Authority (ACMA), said checks made on that particular scam showed regulation was working, saying "the traffic was identified, notifications were passed upstream and blocking occurred".

"The apparent sources were multiple overseas telcos, and the ACMA did not identify non-compliance by an Australian telco," the regulator said in a statement.

Mr Maher said Aussie Broadband had made "significant progress" in the past month to reduce the number of scams.

"We're working as hard as we can, but we need many more pieces of information to be shared with us to solve the problem and we're working hard to do that," he said.

"We are the largest wholesaler in the market and therefore we would have a higher proportion of scam calls."

Symbio warned by the regulator over scam activity

The regulator warned Symbio in 2024, after finding the company was not properly investigating scam calls and had failed to quickly share information with other telcos.

At the time, ACMA said it would be "closely monitoring Symbio's compliance with the rules and would not hesitate to take stronger action if future non-compliance is found".

Symbio was also warned in 2022 over failing to investigate and trace scam calls.

Ms Hicks said it was disappointing the company had faced no financial penalties.

She said TPG couldn't simply "turn off another telco" from its Vodafone network.

"The challenge is that we often have milliseconds to determine when a call comes in, if it's legitimate or if it is a scam."

TPG denied its decision to public criticise its competitor was motivated by commercial rivalry.

"We are bringing this out because we're trying to protect Australians and we're trying to protect our customers," Ms Hicks said.

Reducing the number of scam calls will be of particular importance to telcos next year, with the full introduction of Australia's Scams Prevention Framework (SPF).

The regulator expects it will require telcos to meet strict new obligations to prevent scam calls using Australian numbers and strengthen requirements to know customers and traffic passing through networks.

Companies who fail will be liable to compensate customers and pay stiff penalties of up to $11 million.

ACMA said telcos had reported blocking more than 3.12 billion scam calls since December 2020 and 1.11 billion texts since July 2022, under the existing code.

TPG is not the only one raising concerns about Symbio's network.

Cybercrime investigator Dan Halpin independently examined 8,000 numbers reported by members of the public to his scam phone number platform.

He found Symbio was the number one carrier linked to suspect numbers, even more than Telstra, which has a much larger customer base.

Mr Halpin said Symbio's business model of selling numbers to be used for internet-based calls was attractive to scammers.

"[Symbio] specialise in selling those phone numbers … to individuals in bulk. So the scammers may use or purchase a 100 block of those phone numbers and then they can quickly rotate through those numbers in case they're flagged," he said.

The ABC asked Optus and Telstra if they had experienced high volumes of scam calls which could be traced back to Aussie Broadband, but both declined to provide specifics.

Optus said there was no single carrier that the majority of scam calls consistently originated from.