The short answer
Say what happened, what it cost you, and what you want done about it, in one page, in writing, using the word “complaint”. Add the one sentence that invokes your legal rights for your situation — there’s a menu below — and keep the date you sent it.
What to do today: copy the template on this page, fill in the brackets, add your sentence from the menu, and send it. Twenty minutes.
Why boring beats angry
The person opening your letter handles dozens a day. They are not the person who wronged you, and they sort everything into two piles: easy to resolve, and easy to ignore.
A page of fury goes in the second pile. So does an essay — if the facts are on page three, nobody reaches them. What lands in the first pile is short, dated, specific, and quietly signals that you know the process: the word “complaint”, a clear ask, and one statutory reference. Polite, boring and precise reads as this person will escalate, and win.
What goes in the letter?
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The word “complaint”, first line
For a financial firm it triggers the FCA’s complaint-handling rules; for everyone else it starts their own published procedure. “I’m unhappy” triggers nothing.
“I am making a formal complaint.” -
What happened, with dates
Two or three sentences. What you bought or paid for, the reference number, what went wrong, when.
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What it cost you
The amount, plus knock-on costs — a replacement bought at short notice, calls, a wasted day. Real numbers, not rhetoric.
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What you want
Refund, repair, the service completed, compensation. Name it. Letters that don’t say what they want get replies that don’t offer anything.
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Your sentence from the menu below
The one line that shows you know your rights. It changes how the letter is routed and how seriously it’s read.
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The escalation line
That you’ll refer it to the ombudsman if there’s no final response in time, and that you’re keeping a record of dates. Stated once, calmly. Not a threat — a fact about the process.
The template
Subject: Formal complaint — [account or order number]
Dear [Company name],
I am making a formal complaint. Please investigate it under your complaints procedure and send me a written final response.
On [date] I [bought / paid for / took out] [the thing], reference [number]. [What went wrong, in one or two sentences, with dates.]
This has cost me [£ amount], plus [any knock-on costs].
To put this right, I want [refund of £X / repair / the service completed / compensation of £Y].
[Your sentence from the menu below.]
Please acknowledge this complaint and give me your reference number. If I do not receive your final response within [eight weeks / the required period], I will refer the matter to [the relevant ombudsman]. I am keeping a record of all dates and correspondence.
Yours faithfully,
[Name]
[Address on the account]
Which sentence do I add?
Pick the one that fits. One is enough — stacking three reads as cosplay.
Paid by credit card, item over £100: “As I paid by credit card, I hold you jointly and severally liable under section 75 of the Consumer Credit Act 1974.”
Faulty goods: “Under the Consumer Rights Act 2015, goods must be of satisfactory quality, fit for purpose and as described, and these were not.”
A service done badly: “Under section 49 of the Consumer Rights Act 2015, the service should have been performed with reasonable care and skill.”
A scam or payment problem with a bank: “As this complaint concerns a payment, you are required to resolve it within 15 business days.” This halves their clock, and most people never invoke it.
Flight delay or cancellation: “I am claiming the fixed compensation due under UK261 for a delay of [X hours] on a flight of [distance band].”
None of these fit? Leave the slot out — the letter still works. Start here to check which scheme covers your problem.
What should I leave out?
Deadlines you invented. “Respond in 48 hours or else” gets ignored — the rules already give them a period, and pretending otherwise signals you don’t know it.
Threats you won’t keep. Court gets mentioned once, later, in a proper letter before action — not in paragraph one of a first complaint.
The essay. Background beyond the facts dilutes the facts. One page.
The CC list. Copying the chief executive, the regulator and a TV consumer show into a first letter reads as noise. There is an escalation ladder; this is rung one.
Anger doing the work of evidence. Every sentence of fury is a sentence of fact you didn’t write.
Email, web form or post?
Whatever produces a dated copy you keep. Email is usually best — the sent record makes itself. If they force a web form, screenshot the completed form before submitting and note the reference on the confirmation screen. Post only if you must, and get free proof of postage at the counter if you do.
Phone calls and social media are for chasing, not complaining — you can’t attach a tweet to an ombudsman referral. If you’ve already complained by phone, send the letter anyway “to confirm my complaint of [date]”. That rescues the earlier date.
Send it to the complaints address, not your usual contact. It’s on their website, usually under “complaints” in the footer — the same page that must name their ombudsman.
What happens after you send it?
They should acknowledge it — financial firms promptly, with a reference. Chase in writing at four weeks if you’ve heard nothing. Their clock: eight weeks for most sectors, six for phone and broadband complaints raised on or after 8 April 2026, and fifteen business days for payment complaints. From there, the process takes over: how complaining works, start to finish.
We’ll watch your dates
Enter the dates from your own complaint and we’ll email you ahead of each deadline on this page — a week before the company’s time is up, and again a month and a week before your window to escalate closes. Nothing else is ever sent.
We store the dates and your address, nothing else. We delete both once the dates have passed, and every email has a one-click removal link.
Common questions
Does it have to be a letter, or is email fine?
Email is fine — written and dated is what matters, and email keeps its own record. “Letter” here means the document, not the postage.
Should I say I’ll take them to court?
Not in this letter. The credible escalation is the ombudsman — free, and you’ll actually do it. Court talk comes later, if ever, in a formal letter before action.
How much should I ask for?
Your actual loss, plus real knock-on costs, stated specifically. Don’t invent a distress figure — if it reaches the ombudsman, they set that, and they add 8% interest on money you were kept out of. Asking for something concrete beats asking for “compensation”.
Sources: Consumer Credit Act 1974, section 75; Consumer Rights Act 2015; FCA Handbook DISP 1.6 and Ofcom’s approved ADR schemes, as linked from how complaining works.
Did a letter like this get you a result?