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How do I make a complaint to my energy supplier?

A worried-looking woman sits at her kitchen table looking at bills.
11 January 2024

Having trouble with your energy supplier? Lots of us do. Here’s what to do if you want to make a complaint.

Making a complaint to your gas or electricity supplier can be frustrating and time-consuming, especially for people who are not familiar with their energy company’s processes – which is most of us.

Our advice line deals with thousands of cases a year where people haven’t received the right service from their energy company. In many of these cases we recommend that the customer makes a formal complaint. Here we outline the steps that we find to be most effective.

You can raise a complaint with your supplier via phone, email, online chat or letter. However, if possible, and if you have access to the internet, we recommend you use Resolver for raising and following up complaints – though not all energy companies use this service. 

Resolver is a free online and independent tool for resolving issues between customers and organisations such as energy companies. They will help you to write the complaint letter, let you know your rights and guide you through the complaints process. They will also support you to take your complaint to the Energy Ombudsman if you are not satisfied with the response you get from your supplier. Even if you raised your complaint directly to the supplier you can still use Resolver to follow up on your complaint. 

Reasons to complain to your energy supplier

There are many reasons why you might want to raise a formal complaint with your gas or electricity supplier. Some of the most common are when they:

Suppliers deal with complaints all the time. And it’s in their interests to do it well, as it helps them improve their standards, and will strengthen consumers’ trust in the energy market.  

Bear in mind that they have set procedures that they must follow regardless of how you make the complaint. You’ll get the same result if you’re polite as you will if you’re angry. 

Poor customer service is one of the most common reasons why people make a complaint to their energy supplier.

Before raising a complaint to your energy supplier

Before contacting your supplier to complain, it’s a good idea to make notes so that you are clear and remember everything you want to say. You might want to include some or all of the following:

You will also need to have your account number handy, and a current meter reading (even if you have a smart meter).

If you’re complaining on someone else’s behalf, remember to have their address and phone number ready.

What you can ask your energy supplier to do

You can ask your supplier for different ways to fix your problem. For example:

Priority Services Register

It is important to tell your supplier if anyone in your home could be considered vulnerable – for example if they have physical or mental health issues, if they are over 60 or under 5, or if they have difficulty understanding English.

If your supplier knows about vulnerabilities in your household, this can add weight to your complaint. And going forward, you may receive better service or a more affordable debt repayment plan. 

Read more about the energy companies’ priority services registers here.

Complaining to your energy supplier directly by email or letter 

To raise a complaint directly with your supplier by email or letter, take the following steps:

  1. Find your energy company’s email or postal address on your bill or on their website.
  2. Make it clear in the first paragraph of the letter or in the subject line of the email that you wish to raise a complaint.
  3. Include all the information you have prepared before making the complaint (as listed above).
  4. Ask them to let you know that they have received your complaint and for a complaint reference number.

Complaining to your energy supplier directly over the phone

You can find your energy supplier’s phone number on your bill or on their website.

  1. When you get through, say: “I want to make a complaint” and ask to speak to the complaints team. This team knows more about how to solve problems than the general customer service teams.
  2. When discussing your issue with the supplier, refer to your notes (see above) to make sure you provide all the information you have prepared.
  3. If you think you might be eligible for the company’s priority services register, ask to be added to this. Find out why this is a good idea here.
  4. Ask for your complaint reference number and make a note of it.
  5. Before ending the call, ensure that the complaint is still open and will be looked into. They may try and close the complaint by thanking you for your ‘feedback’ or asking if you’re happy with the outcome of the call.  


Sometimes, energy companies will give compensation to a customer that has a justified complaint about the service they have received. The decision about whether to pay compensation and how much is made by energy supplier. It may not be as much as you are expecting, and you may get nothing at all. 

If you’re not happy with the amount of compensation you’re offered, reject the offer and ask for a different amount.

In our experience, it’s a good idea to ask for compensation for every separate problem you have.

Energy Ombudsman

If you are not satisfied with how your complaint has been dealt with by your energy company, you can register your dispute with the Energy Ombudsman. This is an independent organisation which acts as an impartial mediator to resolve disputes between consumers and energy suppliers.

Generally, this can only be done eight weeks (56 days) after you raise a complaint with your supplier. But you can approach the Ombudsman sooner if your supplier has sent you a ‘deadlock letter’ stating that they and you have been unable to come to an agreement on how your complaint should be resolved.

Registering the dispute with the Ombudsman

The Energy Ombudsman website is the fastest way to register the dispute, but you can also do this by phone (0330 440 1624), email ( or post (Energy Ombudsman, P.O. Box 966, Warrington, WA4 9DF).

You can request a translator or advocate if required.

The ombudsman is likely to ask for evidence such as emails, letters and bills. It may also be helpful to provide a list of the time and date of calls, the names of the people spoken to and the details of what was said.

It takes around six weeks for the Ombudsman to make an assessment. The possible outcomes could be that the supplier:

It is not the role of the Ombudsman to punish suppliers or to make them change how they operate.

The decision

If you feel your complaint hasn’t been adequately addressed, you can reject all or part of the decision. Usually, the Ombudsman decision is final, but an appeal can be made if a mistake has happened or new information has come to light.

If you and your supplier accept the decision, the supplier is legally bound to implement it. The investigating officer will track progress and to keep the supplier on track.

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