Indigenous Australians in some of the nation's most remote communities are being handed exorbitant Telstra phone bills, with data suggesting more than $360,000 of debt has been accrued across just 74 cases in three states.

Tiwi Islands woman Anne Marie Puruntatameri lives on the island community of Pirlangimpi, but renal dialysis sees her spend weeks at a time away at a clinic in Darwin.

Three times a week she receives treatment for more than four hours.

Separated from family and friends on the islands, she eventually decided to get a mobile phone and headed to the Telstra store.

"I went to the shop and they asked me if I wanted a phone on a plan, and I said 'Yeah', without knowing about the big bills I was going to get," she said.

Ms Puruntatameri showed staff evidence of her Centrelink income, signed a contract, and walked out with a mobile phone on a plan.

Some time later, she received a bill asking nearly $6,000.

"I was paying $100 every fortnight," she said.

"There was frustration. I couldn't sleep. My mind was on the bill.

"I was panicking. How am I going to pay this bill? It's too much."

Shortly after signing up to a contract, Ms Puruntatameri received this bill. ( ABC Radio Darwin: Jesse Thompson )

$30,000 debt in community of 1,100

The small community of Gunbalanya, perched at the meeting place of Kakadu National Park and West Arnhem Land, is home to about 1,100 people.

At least three have been in situations similar to Ms Puruntatameri's, racking up at least $30,000 between them.

Gunbalanya is home to about 1,100 people and is isolated by floodwater for several months each year. ( ABC Radio Darwin: Jesse Thompson )

Among them was a man on a disability pension who was sold multiple phones and eventually handed a $10,000 bill.

The financial counsellor who worked to get it waived, HK Training and Consultancy's Veronica Johnson, said the case was typical compared to others she had encountered.

"It starts off with a debt, like a plan of maybe $100 a month, but he didn't have a clear understanding of what happens when you go over your data," Ms Johnson explained.

"You can be charged up to $10 per gigabyte, and this is when that gets out of control and the debt starts getting out of control.

"Suddenly there's cancellation fees, there's broken contract fees.

"A lot of the phones are from $800 to $1,200 per phone, so you add that up with multiple phones and you can get a debt into the thousands."

Uncovering cases of bill shock

Based in suburban Darwin, Ms Johnson and her colleagues have begun to uncover more cases of bill shock in the nearby communities in which they do outreach work.

According to manager Toni Cork, many Indigenous people have become victims of improper credit checks at the point of sale, alongside their own generally poor financial literacy.

They become entrenched in further stress when their debts are sold on to collectors.

"Then the harassment starts, which adds pressure and stress and when the stress gets to boiling point, they will see a money management worker or some other person they trust," Ms Cork said.

Financial counsellors Veronica Johnson and Toni Cork have been doing outreach work in West Arnhem Land and beyond. ( ABC Radio Darwin: Jesse Thompson )

Several counsellors believe that staff commissions could be motivating Telstra staff to upsell devices.

Telstra confirmed its employees are offered sales incentives on varying products.

Counsellors also spoke of negligent sales tactics.

"We've been made aware of situations where a client might have gone in to buy one handset [and] they've walked out with two or three, maybe even a free iPad," Robert Rooth from Anglicare NT's Money Matters program said.

Several also alleged that people were being signed up to expensive mobile devices even though they lived in areas without internet access.

"I always say, it's all about knowing your client," Mr Rooth said.

"If you don't know your client then how can you sell them the right, most suitable package?"

Debts in Darwin and beyond

In a statement, a Telstra spokesperson said these cases represented "a tiny fraction of our overall credit performance".

But recent data collation between groups working in the Northern Territory, Western Australia, and APY Lands in South Australia shows the scale of the issue.

"We're talking big money," Ms Cork said.

"You're seeing it in Aboriginal town camps, in the West Arnhem Land communities, in the communities in the APY Lands, remote and urban Alice Springs communities and also in Western Australia — there's a lot in Broome as well."

Some debts among the data are based on estimates and other amounts are unknown, but figures suggest agencies have uncovered at least $360,000 in debt across 74 listed cases.

Map A map of phone debts

In many cases the clients are highly disadvantaged, receiving either welfare payments or low incomes.

In addition, many cite being put on multiple contracts, not understanding what they'd been sold and experiencing pressuring sales tactics.

"In one case, we had a client that couldn't even sign his name; the contract was signed with a cross," Ms Johnson said.

In Broome and nearby communities, financial consulting group Broome Circle has worked to get 23 cases costing $93,000 waived.

In one case, Ms Johnson helped waive a gentleman's $10,000 of debt. ( ABC Radio Darwin: Jesse Thompson )

Similarly, Ms Johnson believed she had been able to get about $60,000 of the estimated $70,000 in debt she had come across waived, based on mitigating circumstances such as disadvantage, poor literacy, and unconscionable conduct.

In Ms Puruntatameri's case, Ms Johnson was able to negotiate the debt down by thousands of dollars, and the Tiwi Islands woman now educates others about the merit of pre-paid plans.

Like hers, many cases have made their way to financial counsellors from renal clinics.

But advocates have concerns that more people could be paying unfairly solicited debts without seeking help, as many cases were only discovered incidentally.

'Unconscionable conduct': consumer body

Una Lawrence, policy director of the Australian Communications Consumer Action Network (ACCAN), said procedures needed to account for the vulnerability of clients, who rarely speak English as a first language and thus are unlikely to understand the commitments they are entering into.

"The other problem is there aren't appropriate credit assessments done at point of sale so, for example, there's very limited enquiries as to the individual's income," Ms Lawrence said.

"[In] the cases that we've come across, the consumers have been on very restricted, low incomes with a lot of other financial commitments, and they really haven't been able to afford to repay these items."

But if clients have signed on to these contracts, has the service provider done anything wrong?

"Under Australian consumer law, it could be argued that these are examples of unconscionable conduct, because these are vulnerable consumers who could be considered to be taken advantage of," Ms Lawrence said.

The telecommunications giant said it was working to improve practices at the point of sale. ( AAP: Joel Carrett, file photo )

A Telstra spokesperson emphasised that undertaking credit checks is a key part of their process for new customers, and said measures were in place to ensure correct procedures were followed.

"We are aware of a small number of cases where financial counselling services have raised an issue with us on behalf of a customer," the spokesperson's statement read.

"In these cases, we have worked with both the agency and the individual customer through our complaints process to come to a suitable resolution."

Additionally, the spokesperson said the company was taking steps to decrease the risk of sales like Ms Puruntatameri's occurring.

They are strengthening credit assessment processes to decrease the risk of multi-product sales, increasing checks on existing customers adding new contracts, and promoting a single point of contact for financial counsellors and community lawyers.

In a submission to a current review of the Telecommunications Consumer Protections Code, overseen by the Australian Communications and Media Authority (ACMA), ACCAN has asked for tighter provisions around the point of sale and credit assessments.

The ABC understands the ACCC has been notified of this issue, but their media policy prevents them from speaking about potential investigations.