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How to Make a Complaint About Your Energy Supplier

When you sign a contract with an energy supplier, you have certain reasonable expectations: that your bills will arrive promptly and be accurate, that your meter will accurately record your energy usage, and that you'll be notified of any price hikes in advance. If your energy supplier fails at any of these things, you’re within your rights to lodge a complaint. A formal complaint makes your energy supplier aware of their failings and can compel them to resolve the issue and sometimes pay you compensation.

You should first use your supplier’s internal complaints process to raise issues. If they fail to respond promptly or you’re not satisfied with their response, you can escalate the matter to the Energy Ombudsman. You may also want to raise the issue with Citizens Advice, which compiles data on energy company complaints.

Lauren Smith
Mike Rowe
Written by Lauren Smith
Edited by Mike Rowe
04 November 2025
9 mins read

Why might you need to make a complaint about your energy supplier?

Energy suppliers don’t always get it right. The following common failings are grounds for raising a complaint:

1. Billing Issues

A Guardian analysis of cases submitted to the Energy Ombudsman found that billing disputes accounted for 54% of all complaints about energy suppliers over the last five years. These include:

  • Inaccurate bills, including those based on erroneous meter readings or, when meter readings aren’t available, with excessive estimated charges. You should also complain if your bill includes charges you don't recognise.

  • Delayed or missing bills: Your energy supplier is legally required to send paper or digital bills outlining your charges.

  • Back-billing disputes: When the energy supplier is at fault for inaccurate billing, they can only back-bill for energy use within the last 12 months but not before.

  • Direct debit issues, such as charges that don’t match bills.

  • Refusal to refund credit balance: If you've built up a high credit balance, you can ask the supplier to refund it. They're supposed to do so promptly, usually within 10 working days, or explain why they won't. Failure to meet these obligations is grounds for a complaint.

2. Meter problems

Electricity and gas meters sometimes malfunction, recording inaccurate figures that can result in erroneous bills.

Smart meters are supposed to be more accurate but can still glitch: Citizens Advice found that 49% of the consumers it helped with billing issues had smart meters.

In extreme cases, energy suppliers can even associate the wrong meter with your account and bill you for the energy use of a neighbour or another stranger.

3. Tariff issues

You should complain if your supplier moves you onto a new tariff without your consent and before the expiry date of your old tariff or, if you’re on a default tariff, if your supplier is charging you higher per unit and standing charge rates than permitted under the energy price cap.

4. Customer service failings

You can complain if you're unable to easily contact your supplier, such as due to excessive phone waiting times, or if you encounter rude treatment when you do so. You can also complain if your supplier fails to handle your complaint in a timely manner.

5. Switching glitches

You have the right to a fast, smooth transfer of energy supply. You should complain if the supply isn’t handed over to your new chosen supplier within five working days or if your old supplier doesn’t promptly issue you with a final bill.

Sometimes, clerical errors may lead to your supply being moved without your consent or knowledge, a mistake known as an “erroneous transfer” for which you should be financially compensated.

6. Issues with debt

You should file a complaint if your supplier is pursuing you for money you don’t believe you owe. If the debt is yours, energy suppliers have a legal obligation to work with you to clear the balance, including by offering affordable repayment plans. They should only disconnect your supply as a last resort. Additionally, debt collection agencies used by energy suppliers are prohibited from threatening consumers. If your energy supplier has failed in any of these ways, you’re within your rights to complain.

7. Communication lapses

Energy suppliers are required to promptly notify you of tariff expiry dates and price hikes. You can complain about their failure to do so.

In cases of repeated or unannounced power cuts, your retail energy supplier is unlikely to be the culprit, as they don’t operate or maintain the electricity grid. Instead, you should contact your distribution network operator and, if they don’t provide adequate assistance, the Energy Networks Association or Citizens Advice. In some rare cases, your supply may be interrupted due to meter problems or debt, which are matters you should raise with your supplier.

How to make a complaint about your energy supplier

You should first raise your concerns with your energy supplier itself and give them a chance to resolve the issue. Sometimes energy suppliers have dedicated channels for complaints, but otherwise, you should reach out through standard customer service lines. You typically have the option of raising your issues over the phone, through email, or via web chat.

Before you contact the supplier, you should assemble any relevant evidence. This may include bills, bank statements, and photos of meter readings. You should also familiarise yourself with your rights as an energy consumer and the regulations the energy supplier must follow, for example, transferring your supply within five working days.

If you phone, you should always make notes about the conversation, including the date and time of the call, the name of the person you spoke to, and what was discussed. In complex cases, it’s a good idea to follow up the phone call with an email or letter so there’s a paper trail. If you’re unsure what to say, you can use the template letters provided by Citizens Advice as a guide.

In all communication with your energy supplier, you should include your account number (this is printed on any bills they send) and any case or complaint reference numbers.

Sometimes you may be able to resolve the issue with simple communication. In other cases, you may need to file a formal complaint with the supplier, using procedures outlined on their website or on your energy bills.

What happens once you make a complaint?

After you make an internal complaint, energy suppliers have to follow certain procedures and timelines set out by the energy regulator Ofgem.

After you submit the complaint, they’ll acknowledge they’ve received it within a few working days and begin an investigation into the issues you’ve raised. They should keep in touch with you during this investigation.

The supplier should come back to you within eight weeks with a response. If they uphold your complaint, energy suppliers may offer:

  • To fix incorrect bills

  • To refund you for money incorrectly billed

  • To stop pursuing you for a debt you don’t owe

  • To fix meters

  • An affordable and realistic repayment plan for debt

  • Financial compensation

  • An apology

What if you don’t receive an adequate response?

If you’re not satisfied with their offer, you can reject it and request a deadlock letter. This is a formal letter stating that you and the supplier are unable to reach a mutually satisfactory resolution to the issue. It also provides information on escalating the complaint to the Energy Ombudsman.

If the energy supplier fails to get back to you within the required eight weeks, you can approach the Energy Ombudsman without a deadlock letter.

What is the Energy Ombudsman?

The Energy Ombudsman is an independent, impartial arbitrator of disputes between energy companies and their customers. The service is free to use and can lead to resolutions that are legally binding for the company (but not the consumer).

The Energy Ombudsman handled 123,000 disputes in 2023, the last year for which full data is available. In more than three-quarters of cases (77%), they upheld the complaint, deciding in favour of the consumer. As a result of their decisions, energy companies handed more than £16 million to wronged customers that year.

How do you file a complaint with the Energy Ombudsman?

You can register your dispute with the Energy Ombudsman through its website, over the phone (0330 440 1624), via email (enquiry@energyombudsman.org), or through the post.

After opening a case, you have 14 days to submit supporting information or evidence to the Ombudsman. This supporting information may include:

  • Records of communication between you and the supplier about the complaint, including emails, letters, chat transcripts, and notes about or recordings of phone conversations.

  • Copies of bills

  • Bank statements showing payments made

  • Photos of meter readings

  • Evidence showing how you’ve been impacted by the energy supplier’s failings and  the dispute

The supplier also has the opportunity to provide evidence supporting their case. In some cases, just the fact that you've asked the Energy Ombudsman to intervene is enough to persuade the company to admit fault and offer a resolution. If they don’t, the ombudsman will begin its review of the case.

When reviewing the dispute, the ombudsman considers not just the supplied evidence but also the law, regulations for energy suppliers, and standards of practice in the industry. In most cases, the ombudsman will reach a decision within six weeks of receiving evidence from both parties, although some complex cases take longer.

Depending on the outcome of the case, the ombudsman might require the supplier to:

  • Take action, such as changing your tariff, cancelling debt, or crediting your account

  • Apologise

  • Consider recommendations to prevent similar situations from arising again

If you accept the proposed remedy, the supplier is legally required to carry it out and should do so within 28 days.

If you don’t accept the proposed remedy, you can continue to pursue the supplier through the court system.

How can Citizens Advice help with energy supplier complaints?

Citizens Advice can advise you on lodging a complaint with your energy supplier or the Energy Ombudsman. This is especially true if your case is complex, you’re struggling to get a response from your supplier, or you’re vulnerable.

You can also register your complaint with Citizens Advice. While they don’t engage with energy suppliers on your behalf and cannot help you reach an individual resolution, they do record data about complaints they receive and share this information with energy regulator Ofgem and the Energy Ombudsman.

Citizens Advice also produces league tables showing which energy companies attract the most complaints, encouraging companies to do better.

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