Mechanic overcharged or fixed the wrong thing? Your ACL options

You dropped your car off for a brake pad replacement and picked it up with a bill twice what you were quoted — plus a list of extra work you never approved. Or the mechanic fixed something, you drove away, and the same warning light came back on within a week. Or they charged you for parts you're pretty sure weren't fitted. These situations are more common than they should be, and a lot of people assume there's nothing they can do because they've already handed over the money or they don't have the technical knowledge to argue back.

The Australian Consumer Law (ACL) covers services as well as goods. That means the same framework that protects you when a washing machine breaks down also applies when a mechanic does shoddy work, charges you for services they didn't perform, or blows past a quote without your authorisation. Here's how to use it.

Quick answer

When a mechanic overcharges you, performs work you didn't authorise, or does a poor job, you have rights under the consumer guarantees in the ACL — specifically section 60 (due care and skill) and section 61 (fitness for purpose). If the service wasn't performed competently, you can ask for the problem to be fixed at no extra cost, a price reduction, or a refund of all or part of what you paid. If the mechanic did work you never agreed to, you generally don't have to pay for it. Start with a written complaint to the workshop. If they refuse to engage, escalate to your state's Fair Trading body or a consumer tribunal.

What the law actually says

The ACL applies to any service supplied by a business in trade or commerce. Taking your car to a mechanic — whether it's a sole trader, a franchise workshop, or a dealership — is a service transaction covered by the ACL.

Three guarantees are most relevant to mechanic disputes:

• Section 60 — Due care and skill. The mechanic must perform the service with the care and skill you'd reasonably expect from a competent professional in that trade. If they replace the wrong part, leave a bolt loose, or cause new damage while doing the work, the guarantee is breached.
• Section 61 — Fitness for purpose. If you told the mechanic what outcome you needed ("I need this car to pass a roadworthy inspection" or "I need it reliable enough for a long drive next weekend"), the service must achieve that result, provided it was a reasonable thing to promise.
• Section 62 — Reasonable time. If no timeframe was agreed, the service must be completed within a reasonable time. This is less commonly the basis of a dispute, but relevant if the workshop has held your car for weeks without explanation.

On top of these guarantees, there's a separate protection around pricing. Under section 51 of the ACL, a business must not charge more than the price they represented. If a mechanic gave you a written quote of $400 and then charged $900 without calling you first to get approval, that's not just bad practice — it may breach the ACL. Most states and territories also have specific motor vehicle repair legislation that requires written authorisation before work can proceed above a certain threshold. Check your state's Fair Trading body for the local rules, because the thresholds and requirements vary.

For remedies when a service guarantee is breached, section 267 of the ACL sets out your options. If the failure is major — the service has created an unsafe situation, the car still can't do what you needed it to do, or the problem is so significant that a reasonable consumer wouldn't have engaged the mechanic had they known — you can cancel the contract and get a refund, or keep the outcome and seek compensation for the drop in value. For a non-major failure, the mechanic gets a chance to fix the problem first. If they don't fix it within a reasonable time, or they refuse, you can have it fixed elsewhere and recover the cost.

You can read more about how these remedies work for services generally in our services that go wrong guide.

When this applies (and when it doesn't)

The consumer guarantees apply when:

• You paid a business (not a friend or a private individual doing you a favour) to work on your vehicle.
• The dispute is about the quality of the work, the price charged, or work done without your authorisation.
• You can show you engaged the mechanic and paid them — a receipt, a bank statement, a tax invoice, or even a text message confirming the booking.

The guarantees are less likely to help when:

• The mechanic disclosed a risk before doing the work and you accepted it. If they said "I'll try to free this seized bolt but there's a chance it'll snap and cost more to fix" and you said go ahead, the outcome may not be a breach.
• The new problem is unrelated to the work done. If you had your brakes serviced and then your alternator fails two weeks later, you'd need to show a link between the service and the new fault.
• You agreed to a "time and materials" arrangement with no cap. In that case, a high bill isn't automatically a breach — though the work still needs to be done with due care and skill.
• The vehicle is used exclusively for business purposes and the purchase price exceeds $100,000. Most personal vehicles are well within the ACL's scope.

One thing worth knowing: the ACL's protections for services sit alongside, not instead of, any rights you have under a specific quote or contract. If the mechanic gave you a written quote and then charged more without your approval, you have a straightforward contract claim as well as an ACL claim.

What to do today

Acting methodically matters here. A well-documented complaint is far harder to dismiss than an angry phone call.

1. Gather everything you have. The original quote (written or text message), the final invoice, any communications with the workshop (texts, emails, voicemails), and photos of the car before and after if you have them. If you don't have a written quote, write down from memory what was discussed and when.
2. Get an independent assessment if the work was poor. If the mechanic's work was substandard, a written assessment from another qualified mechanic is strong evidence. Keep the receipt for that assessment — it's a recoverable cost if you escalate.
3. Write a formal complaint to the workshop. Email is best because it creates a timestamp and a paper trail. Describe what was agreed, what was done, and how that falls short of what the ACL requires. Reference section 60 (due care and skill) and/or the pricing issue. State clearly what you want — a refund of the overcharge, a free repair of the botched work, or compensation — and give a deadline of 14 days.
4. Be specific about the amount. "I was quoted $420 and charged $870 without authorisation. I'm seeking a refund of the $450 difference" is much more effective than a general complaint that the bill was too high.
5. Don't let them hold your car hostage. In most states, a repairer cannot hold your vehicle unless they have a legitimate lien for unpaid work you authorised. If you're in a dispute about an overcharge, get advice from your state's Fair Trading body before leaving the car there indefinitely.

Not sure how to word the complaint letter? fairgo can draft one for you in about 90 seconds — the wizard identifies the relevant ACL sections and produces a letter you send under your own name.

What if the business refuses

If the workshop ignores your complaint or tells you the charge stands, you have several escalation paths:

• Your state's Fair Trading body. Every state and territory has a free conciliation service for consumer disputes. For motor vehicle repair disputes specifically, many Fair Trading offices have dedicated automotive complaint teams with industry knowledge. They contact the business on your behalf and try to broker a resolution. Find your state's contact at /agencies.
• Your state consumer tribunal. If conciliation doesn't resolve things, you can file at NCAT (NSW), VCAT (Victoria), QCAT (Queensland), SAT (Western Australia), SACAT (South Australia), or the equivalent in your state. Filing fees are modest and you don't need a lawyer. The tribunal guide explains how to choose the right one and what to expect.
• Motor vehicle industry-specific bodies. Some states have separate dispute resolution schemes for the automotive industry. Your state's Fair Trading body can point you to these.
• Small claims or magistrates court. For larger amounts, or if the tribunal doesn't have jurisdiction over your specific claim, the magistrates court is an option. This is less common for mechanic disputes but worth knowing about.

The demand letter is often enough. Workshops that know they've overcharged or done poor work frequently settle once a properly written letter citing the ACL arrives — because they know a tribunal will likely find against them. See what to do when a business refuses for the full escalation playbook.

Common mistakes

These are the patterns that weaken otherwise strong complaints:

• Paying first, then complaining. Once the money is paid, recovering it is harder than disputing a charge before you hand it over. If you're presented with an invoice that's much higher than the quote, ask for an itemised breakdown before paying and note your objection in writing.
• Only complaining by phone. Phone calls are easy to deny or misremember. Always follow up a phone conversation with an email summarising what was said: "As discussed this morning, I'm disputing the $450 overcharge because no authorisation was sought before the additional work was done."
• Assuming you need to prove the mechanic was negligent. The ACL consumer guarantee doesn't require you to prove negligence in the legal sense. You just need to show the service didn't meet the standard of due care and skill a reasonable consumer would expect.
• Waiting too long. There's no hard deadline in the ACL for service complaints (unlike some other legal claims), but delay weakens your position. The longer you wait, the harder it is to show the problem was caused by the mechanic's work rather than something that happened later.
• Accepting a partial fix that doesn't address the real problem. If the mechanic offers to "look at it again" but the underlying issue is that they charged for work they didn't do, a second inspection doesn't remedy the overcharge. Be clear about what remedy you're actually seeking.
• Going to the ACCC for an individual dispute. The ACCC investigates systemic issues and industry-wide conduct — it doesn't resolve individual consumer complaints. Fair Trading and your state tribunal are the right forums for your specific case.

Mechanic disputes can feel technically intimidating — most of us don't know enough about cars to argue confidently about whether a part needed replacing. That's exactly why the ACL's framework is useful: it shifts the focus from "was this repair technically necessary" to "did the business perform the service with due care and skill, and did they charge what they said they would." Those are questions a tribunal can answer without needing a mechanical engineering degree.

Related reading

• Services that go wrong — your ACL rights explained
• Business refused your refund? Here's what to do next
• NCAT, VCAT, QCAT — which tribunal handles your dispute?

This article is general information about Australian Consumer Law, not legal advice. The ACL is complex and your situation may have details that change the analysis. For advice on your specific case, see your state's Fair Trading body — full list at /agencies.