How to Write a Complaint Letter That Actually Gets Results (UK 2026)

Most complaints fail for the same reasons: they are vague, emotional, or never reach the right person. A good complaint letter is short, factual, and makes it easy for a busy company to say yes. This guide shows you exactly how to write one — and what to do if they say no.

What an effective complaint letter contains

Whether you are complaining to a retailer, a builder, an airline or a finance provider, the same six ingredients do the heavy lifting:

1. Your details and the account/order number — so they can find you instantly.
2. What went wrong, in plain dates and facts — not feelings. "Delivered 14 Jan; faulty on 16 Jan" beats "terrible service".
3. The law or term that supports you — e.g. the Consumer Rights Act 2015 for faulty goods, or the contract you agreed.
4. What you want them to do — repair, replacement, refund, or compensation, with a figure where you can.
5. A clear deadline — 14 days is reasonable for a first response.
6. What you will do next if they do not act — escalate to the ombudsman, ADR scheme, or court.

Tone: firm, not furious

The person reading your letter did not personally wrong you, and they decide whether to help. Keep it polite and businesslike. Anger gives them a reason to dismiss you; calm, specific facts give them a reason to act. Quote what you were promised, state what you received, and let the gap speak for itself.

Before you write, gather your evidence

• Order/booking confirmations, receipts, and contracts.
• Photos or video of any fault or damage, with dates.
• A timeline of contact: who you spoke to and when.
• Any quotes, adverts, or messages showing what was promised.

Keep copies of everything and send important letters so you can prove delivery.

A complaint letter template you can copy

Dear [Company name],

Re: [Account / order / booking reference]

I am writing to complain about [product or service] that I [bought/booked] on
[date]. [State plainly what went wrong and when.]

Under [the Consumer Rights Act 2015 / the terms we agreed], I am entitled to
[a repair, replacement, refund, or compensation]. To put this right I would like
[your specific request, with an amount if relevant].

Please confirm in writing within 14 days how you will resolve this. If I do not
hear from you, I will refer the matter to [the relevant ombudsman / ADR scheme /
the small claims court].

I look forward to your response.

Yours faithfully,
[Your name]
[Your address and contact details]

What to do if they ignore you or say no

A "no" or silence is not the end — it is usually the point where leverage appears:

• Ask for a "deadlock" or final response. Most regulated firms must give one before you can escalate.
• Use the relevant ombudsman or ADR scheme. Financial complaints go to the Financial Ombudsman Service; energy to the Energy Ombudsman; many sectors have a free Alternative Dispute Resolution scheme. They are free to use and their decisions bind the company.
• Consider Section 75 or chargeback. If you paid by credit card (or sometimes debit), your card provider may refund you directly.
• Small claims court. For clear-cut sums, the online money claim service is straightforward and the fee is recoverable if you win.

Common mistakes that sink a complaint

• Complaining to the wrong channel (a tweet instead of the official complaints address).
• Not stating exactly what you want, so the company offers nothing.
• Missing time limits — many schemes have deadlines (often six months from the final response).
• Threatening action you will not take; only mention escalation you are willing to use.

Get these basics right and a surprising number of complaints are resolved with a single letter. If yours is not, the escalation routes above exist precisely because companies know they work.