Guide · Telco overcharge & billing dispute
Overcharged by your telco? You don't have to accept a wrong bill.
Here's the bottom line. A billing error is the telco's mistake, not yours, and you have every right to get it fixed. The escalation ladder in Australia has real teeth: raise it with the provider in writing, and if they stall, the Telecommunications Industry Ombudsman is a free, independent lever they have to answer to. This guide walks you up that ladder, from working out what the charge really is to getting the refund in writing.
Last updated 3 July 2026 · by Alien IT Solutions
First, read the bill properly
You can't dispute a charge you can't name. The people who win open the itemised bill first and point at the exact line.
Pull up the full itemised version, not the summary. Find the charge that looks wrong and work out which of these it is, because the fix differs for each:
- Casual or excess data. You went over the plan's data and got charged per block on top. Common, and often the result of no warning being sent as you approached the cap.
- Out-of-plan usage. Calls, texts or roaming that sit outside your inclusions, sometimes at eye-watering per-unit rates.
- A service you didn't order. An add-on, insurance, a subscription or a premium service that appeared without you asking for it.
- A hardware repayment. A device or accessory being paid off in instalments, sometimes still charging after you thought it was settled.
- A double-charge or duplicate. The same fee billed twice, or a credit that was promised and never applied.
Name the charge before you do anything else. "There's a $40 out-of-plan data charge on last month's bill I want explained" gets a result. "My bill's too high" does not.
Gather your evidence before you escalate
A dispute is won on the paper trail, so build it before you make contact. You want four things in front of you, and once they're lined up the case makes itself:
- The line item. The exact charge, its date and amount, marked on the itemised bill.
- Your plan inclusions. What the plan is meant to cover, and what you were told you'd pay.
- The dates that matter. When you joined, changed plan, or cancelled. A charge dated after a cancellation is a strong hand.
- What was said. If a discount, plan change or cancellation was agreed on a call or chat, note when. In writing is better still.
The gap between what you agreed to and what you were billed is the whole dispute. The clearer you show that gap, the faster it closes.
The escalation ladder
Climb it in order. Each rung only works if you've done the one below it.
Don't skip rungs. Going to the ombudsman before you've given the provider a real chance just sends you back down to rung one.
Contact the provider first, and do it in writing
Start with the telco: they have to be given the chance to fix their own mistake, and a dispute raised in writing is one they can't quietly forget.
Use whatever written channel they offer, the complaints form, the app's message thread, or email. Say what the charge is, why it's wrong, and what you want done, a refund, a credit, or the service stopped. Reference the bill and the date. Writing beats a call for one reason: it leaves a record you can point back to.
Ask for two things every time. First, a reference number for the dispute, so there's proof it exists and a clock on it. Second, the resolution in writing. A promise to "credit it next month" that only lived on a phone call has a way of vanishing. Get it on record, then check the next bill shows the credit. If it doesn't, you reopen the dispute with their own written promise in hand.
The TIO: your real lever when the provider stalls
This is the rung that changes the balance of power, and most people don't know it exists.
The Telecommunications Industry Ombudsman is a free, independent complaints scheme for phone and internet services in Australia. It sits above the telcos, and when it takes on a complaint, the provider has to respond. That's the point: while a dispute is just you versus a call centre, the provider can drag it out. Once it's a matter for the ombudsman, the incentive flips, because unresolved complaints cost them.
The order matters. The TIO is for when the provider has had a fair go and stalled, refused, or gone quiet. So work rung one first: raise it, get your reference number, give them a reasonable chance. If that leads nowhere, take the complaint, your reference number, and your evidence to the ombudsman. For exactly how to lodge and what they need, check the TIO's own current website, the source that stays up to date. It's independent and free to you: the referee doesn't work for the telco.
The disputes that usually get won
If your charge looks like one of these, you're on solid ground.
Out-of-plan and roaming
Excess data, out-of-plan calls, or roaming charges racked up with no warning as you crossed the line. If you were never alerted you were about to be charged, that's a strong position.
Auto-renewed add-ons
An extra, an insurance, or a subscription that quietly renewed after you believed it was cancelled or was only ever meant to be a trial. Charges for something you didn't knowingly keep are worth disputing.
Charges after cancellation
Fees that kept landing after you cancelled the service. A charge dated after your cancellation date, backed by your record of when you cancelled, is one of the cleanest disputes there is.
A plan change that never applied
You agreed a cheaper plan or a discount, it was confirmed, and the bill kept charging the old rate. The gap between what was agreed and what was billed is the entire case.
What not to do
A few moves feel satisfying and make things worse. Avoid them.
Don't just stop paying the bill. Refusing to pay anything to make a point can push the whole account into arrears and cause more damage than the charge you're fighting. The disputed amount is one line; the account is everything. Don't risk everything over one line.
Keep the account current where you can. Pay the part that isn't in dispute, and put the disputed amount in writing so there's a record you raised it and didn't simply refuse to pay. Ask the provider to hold the disputed charge while they investigate, and keep its reference number.
Don't rely on anything said out loud. If it wasn't confirmed in writing, treat it as if it didn't happen. Verbal credits, cancellations and plan changes are where disputes go to die.
This is general information, not legal or financial advice. For your specific situation, the TIO and your own records are the best starting points.
Once the error's fixed, stop it happening again
Winning back one overcharge is a good day. But a bill that produced a billing error is usually a bill that's also just too expensive, on a plan that stopped fitting a while ago.
Getting the wrong charge reversed is a dispute. Getting the plan itself down to what it should cost is a different job, and it's the one that actually lowers the bill every month. Once your dispute is settled, that's the time to look at the whole account with fresh eyes. Our sibling guide covers exactly that: how to cut your telco bill once the error's out of the way.
Questions people ask
Telstra or Optus overcharged me. What do I do first?
Work out exactly what the charge is before you ring anyone. Open the itemised bill, find the line, and name it: casual data, an out-of-plan call, a service you didn't order, a device repayment, or a straight double-charge. Then raise it with the provider in writing and get a reference number for the dispute. Naming the charge first is what turns a vague complaint into one they have to act on.
Do I have to pay a bill I'm disputing?
Don't just stop paying, that can put the whole account into arrears and cause more damage than the disputed amount. The safer play is to keep the account current where you can, pay the part that isn't in dispute, and put the disputed amount in writing so there's a record you raised it. Ask the provider to place a hold on the disputed charge while it's investigated, and keep the reference number.
What is the TIO and when should I contact them?
The Telecommunications Industry Ombudsman is a free, independent scheme for complaints about phone and internet services in Australia. It's the lever you pull when the provider has had a fair chance and stalled or refused. Contact your provider first and give them the reference number and time to fix it. If that goes nowhere, the TIO can take the complaint, and the provider has to respond to it. Check the TIO's own current site for how to lodge.
What counts as a billing error worth disputing?
The common wins are concrete: out-of-plan or roaming charges you weren't warned about, an add-on that auto-renewed after you thought it was cancelled, charges that kept running after you cancelled the service, and a plan change or discount that was agreed but never applied to the bill. If the charge doesn't match what you actually agreed to, it's worth disputing.
How do I prove I was overcharged?
Line up the evidence before you escalate. Get the itemised bill and mark the exact line item. Find your plan inclusions and what you were told you'd pay. Note the dates: when you signed up, changed plan, or cancelled. If a promise was made on a call or in a chat, note when and, if you can, get it in writing. The stronger the paper trail, the faster it resolves.
Should I get the outcome in writing?
Always. A verbal promise to credit your account is worth very little if it never lands on the next bill. Ask for the resolution in writing, an email or a message on record, stating the amount, the reason, and when it'll be applied. Then check the next bill actually shows it. If it doesn't, you reopen the dispute with the written promise in hand.
Don't want to fight the telco yourself?
Send us the bill. The audit is free, we'll find the charges that shouldn't be there, and we can deal with the provider on your behalf so you stay out of the phone queue.
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