A good complaint letter is short, factual and clear about what you want. It is not the place to vent. The reader is usually someone in a customer-services team who did not cause the problem and who can only help if they can see at a glance what happened and what would put it right. Copy the template below, replace everything in square brackets and delete the notes.
The template
The plain-text template shows the blocks in order. In your document, right-align your own address block and the date; everything else sits on the left.
[Your house number and street] [Your town or city] [Your postcode] [Your email address or phone number] [Date in full: 3 March 2026] [Name and job title of the customer services manager, if known] Customer Services [Company name] [Company address] [Postcode] Dear [Ms Okafor / Sir or Madam], Re: [Order number / account number / booking reference] I am writing to complain about [the product or service] which I [bought / booked / received] from your [shop / website / branch] on [date]. [What went wrong, in one or two sentences: the item arrived damaged, the service was not carried out, the repair failed again.] [What you have already done about it: who you spoke to, when, and what they said.] To put this right, I would like you to [refund £X to my original payment method / replace the item / carry out the repair / cancel the contract] within [14 days]. I enclose [copies of the receipt / photographs / the email from your colleague]. I look forward to your reply. You can reach me by [email / phone] at the details above. Yours [sincerely, if you used a name / faithfully, if you did not], [Your signature, if posting] [Your name, printed]
How to fill it in
Use a reference line
The “Re:” line above the first paragraph gives the reader your order, account or booking number before they read a word. It is the single most useful line in the letter, because it lets them find your file while they read.
Say what you bought and when
Name the product or service exactly as it appears on the receipt, and give the date and place of purchase. If you bought online, the order confirmation email has everything you need.
Describe the problem, not your feelings
“The washing machine stopped draining on 20 February, eleven days after delivery” is a fact the company can act on. “I am appalled by the shoddy quality” is not. Keep adjectives out and dates in. If there is a sequence of events, give them in order, one per sentence.
Record what you have already tried
If you have phoned, emailed or visited a branch, say when, who you spoke to and what they promised. This shows you have given the company a fair chance and it stops the reply being “please call our helpline”.
Ask for one specific remedy
Decide what you want before you write: a refund, a replacement, a repair, a cancellation or compensation for a specific cost. Ask for that one thing and give a reasonable deadline, usually 14 days. A letter that asks the company to “do something about it” lets them choose the cheapest option.
Enclose the evidence
Send copies, never originals: receipts, photographs, screenshots of the order page, previous letters or emails. List what you have enclosed so nothing goes missing on their side.
Stay polite and firm
Politeness is tactical. The person reading your letter decides how hard to work for you, and a courteous letter that makes a clear request is far more likely to be resolved quickly than an angry one. Firmness means stating your deadline and what you will do if it passes, without threats.
Email or post?
Email is faster and gives you a timestamped record; post is harder to ignore and some companies’ complaints procedures still ask for it. If you email, put the reference in the subject line and paste the letter into the body with the addresses left out. If you post anything that matters, keep a copy and use a signed-for service so you can prove delivery.
If nothing happens
If the deadline passes with no reply, send a second letter headed “Second letter” with a copy of the first enclosed, and give a shorter deadline. Say in this letter what your next step will be. In the UK that is usually one of:
- The company’s own formal complaints procedure, which many regulated businesses (energy, water, telecoms, financial services, travel) must publish.
- An ombudsman or alternative dispute resolution scheme for that industry, which is free to consumers.
- A claim through your card provider if you paid by card: a chargeback for debit or credit cards, or a claim under Section 75 of the Consumer Credit Act for credit-card purchases of goods or services costing between £100 and £30,000. Both have time limits, so ask your card provider early.
- The small claims track of the county court for sums that are worth the fee and the time.
Keep every letter and reply together with the dates. A tidy file of correspondence is what wins a dispute if it goes further, and it is also what persuades most companies to settle before it does.
Related guides
The layout follows the Business Letter Template; the conventions behind it are in Formal Letter Format, which has a section on letters of complaint. Worked examples are on the Letter Writing Examples page.