Practical letter guide
How to Write a Complaint Letter (UK and US)
A strong complaint letter is clear, factual, and specific about the result you want. Set out what happened in date order, attach your evidence, and make your requested outcome and response deadline explicit.
Quick summary
- Helps with
- Complaints about poor service, faulty products, billing problems or unfair treatment by a business or organisation.
- Usually sent to
- The organisation's complaints team or customer services — check its published complaints procedure for the right address.
- Intended outcome
- A written response that fixes the problem: a refund, correction, apology or specific action within a stated timescale.
Regional notes
UK complaints usually go through the organisation's published complaints procedure first, and many sectors then have a free ombudsman or ADR scheme. In the US, complain to the business first, then escalate to your state attorney general or consumer protection office if the response is unsatisfactory.
On this page
When to use this letter
- Informal contact (calls, chat, an email to support) has not fixed the problem.
- You want a written record that starts the organisation's formal complaints procedure.
- You need a documented complaint before an ombudsman, ADR scheme or regulator will look at your case.
- The issue involves money, repeated failures or something the organisation disputes.
When a different route fits better
- A faulty purchase where you simply want your money back — see the refund request guide instead.
- A dispute about a parking penalty — that has its own appeal process with strict deadlines.
- An emergency (safety, disconnection, eviction) — phone the organisation or the relevant authority first, then follow up in writing.
Before you write
Gather these first — the letter almost writes itself once they are in front of you.
- Account, order or customer reference numbers.
- Dates of every relevant event, call and email, in order.
- Names of anyone you spoke to and what was agreed.
- Copies of receipts, contracts, photos, screenshots or previous replies.
- The organisation's complaints procedure or policy, if published.
- A clear note of the outcome you want and a reasonable response deadline.
UK route: complaints procedure first, then an ombudsman
Most UK organisations — and all regulated ones such as energy suppliers, banks, telecoms providers and public bodies — publish a complaints procedure. Follow it: send your complaint in writing, keep a copy, and note the response time it promises. If the organisation rejects your complaint or ignores it, many sectors have a free independent scheme (for example an ombudsman or an alternative dispute resolution provider) that will only accept your case after you have complained to the organisation first, and often only after a set period or a final response letter. Citizens Advice can tell you which scheme covers your sector.
US route: the business first, then state-level help
The Federal Trade Commission recommends complaining directly to the business first, keeping your letter factual and including copies (never originals) of receipts and records. If the business does not resolve it, escalate to your state attorney general or state consumer protection office. If you paid by credit card, you can also dispute a billing error with your card issuer in writing — federal rules require the dispute to be raised within 60 days of the first statement showing the error.
What makes a strong letter
- State the issue in one sentence at the start.
- List key facts in date order.
- Attach evidence and reference each item directly.
- Ask for a specific resolution and a reasonable deadline.
- Name the escalation route you will use if there is no response.
- Keep the tone firm, professional, and concise.
Letter structure you can follow
- Subject line: Formal Complaint Regarding [issue] — [reference]
- Paragraph 1: What happened and when, in one or two sentences
- Paragraph 2: The key facts in date order, referencing your evidence
- Paragraph 3: The outcome you are requesting and by when
- Closing: How to respond to you, and what you will do if there is no reply
Useful wording
I am writing to make a formal complaint about [issue] under your complaints procedure. My reference is [number].
Please send me a written response within 14 days. If I do not receive a satisfactory reply, I will escalate this to [ombudsman scheme / my state attorney general's office].
Adapt the wording to your facts — no wording guarantees a particular outcome.
Common mistakes
- Mixing several unrelated problems into one letter so no single issue is answered.
- Venting frustration instead of stating facts — anger gives the reader an excuse to dismiss the letter.
- Not saying what outcome you actually want.
- Sending originals of receipts or documents instead of copies.
- Missing the organisation's own complaints address so the letter never enters the formal process.
- Not keeping a dated copy of everything you send.
What happens next
- Most organisations acknowledge a written complaint and give a case reference.
- Expect a substantive reply within the timescale in their complaints procedure — chase in writing if it passes.
- If the final response rejects your complaint, check whether a free ombudsman, ADR scheme (UK) or your state consumer protection office (US) can review it.
- Keep every reply — escalation bodies will ask for the full correspondence trail.
Ready to write yours?
Answer a few guided questions and generate a clear, structured draft you can fully edit before sending.
Sources
- FTC — How to write an effective complaint letter (US)
- FTC — Using credit cards and disputing charges (US)
- Citizens Advice — Consumer help (UK)
Last reviewed 2026-07-13. Processes and deadlines change — always confirm against the official source for your nation or state before relying on a date.
This guide provides general information only. This tool provides AI-assisted drafting support and is not legal advice.