Bizzy writes it with you
Complaint letter generator
Tell Bizzy which company let you down and what happened. Bizzy writes a firm, factual complaint letter with you, and after launch it waits in your case file: change it, print it, or let us send it.
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How the complaint letter generator works
Complain.biz has published 73,599 consumer complaints, and we have watched which ones got an answer and which ones were ignored. Our AI models are trained on thousands of complaint letters and the outcomes they produced. The pattern is clear: the letters that work are not the angriest ones. They are the ones a customer service agent can act on in one read.
That is what Bizzy, our AI complaint writer, does with your story: it asks for the facts a company needs, puts them in the order that works, states what you want and by when, and keeps the tone firm and polite. You check the draft, change what you want and launch it. Your formal letter then waits in your case file, where you can change it, print it or save it as a PDF, or let us send it to the company. The letter is yours.
Sample complaint letter
A parcel marked delivered that never arrived, the complaint we see most. This is the shape of a letter that gets read: a subject line with your reference, five short paragraphs and one clear ask with a deadline. Bizzy writes yours from your own facts.
[Your name]
[Your address]
[Your email address]
12 November 2026
Customer Service
[Company name]
Subject: Formal complaint about order 48213, marked delivered but never received
Dear Customer Service team,
1I am writing to make a formal complaint about order 48213: a pair of wireless headphones I bought on your website on 17 October for $89.90, including delivery.
2Your tracking page shows the parcel as delivered on 24 October at 2:12 pm, but it never arrived. It was not at my door or anywhere nearby, and there is no delivery photo. When I contacted your chat on 26 October, I was told to wait 48 hours. I have now waited 17 days without an update.
3Please refund the full $89.90 to my original payment method, or send a replacement at no extra cost, by 26 November. That is 14 days from the date of this letter.
4I have attached my order confirmation, a screenshot of the tracking page and the transcript of my chat with your team.
5If I have not heard from you by 26 November, I will take this further.
Yours sincerely,
[Your name]
Order 48213
What each paragraph does
- 1The facts: what, when, how much, and your reference.
- 2What went wrong, once and concretely, with the dates of earlier contact.
- 3What you want and by when: a named amount and a deadline.
- 4Your evidence.
- 5A calm close: what happens when the deadline passes.
How to write a complaint letter that gets results
- 1
The facts, in order
What you bought or used, when, where and for how much. Order number, booking reference, account or ticket number. Dates of every contact you already had, and the name of the person you spoke to if you have it.
- 2
What went wrong, in one paragraph
Describe the problem once, concretely. "The parcel was marked delivered on 3 May but never arrived" beats three paragraphs about how you feel. Save the feelings for the last line, if at all.
- 3
What you want, and by when
A refund, a replacement, a repair, compensation for costs you made. Name the amount. Give a reasonable deadline, usually 14 days, and say what you do if you hear nothing: a chargeback or a public complaint.
- 4
Evidence
Attach or link the receipt, photos, screenshots of the chat, the tracking page. One good photo does more than a page of description. Never send originals.
- 5
The right tone
Firm, polite, no threats and no insults. Threats make companies defensive and give them a reason to close the ticket. A calm letter with a deadline is much harder to ignore.
- 6
Send it where it counts, and keep a copy
Use the complaints address, not the sales chat. Note the date you sent it. If the deadline passes, your copy and the dates are what you need for the next step.
Common mistakes
Writing too much
Long letters get skimmed. Half a page is plenty. If the story is long, put the timeline in a short list and keep the paragraphs for the problem and the ask.
Not saying what you want
"Please sort this out" leaves the company free to do nothing. "Refund the 89.90 to my card within 14 days" does not.
Complaining to the wrong place
A social media reply or a chat with sales is not a complaint on file. Send it to the complaints address, or publish it where the company and its next customers can see it.
Giving up after the first no
The first answer is often a template. Reply once, refer to your letter and your deadline, and then escalate. Most results come after the second contact.
Questions about complaint letters
How do I start a complaint letter?
Start with what the complaint is about: your order, booking or account number, what you bought, when, and what you paid. Say in the first sentence that you are making a formal complaint. Skip the small talk: the first lines decide whether the right person reads on.
How do I end a complaint letter?
End with what you want and by when: a refund of a named amount, a replacement or a repair, within 14 days. List what you attached, then close with "Yours sincerely" (or "Sincerely") and your full name. Put your order or account number under your name, so nobody has to look it up.
What is the format of a complaint letter?
Your name and contact details, the date, the company's name, a subject line with your reference number and a greeting. Then three to five short paragraphs: the facts, what went wrong, what you want and by when, and your evidence. End with a sign-off and your full name. Half a page is enough. The sample letter above follows this format.
Should I send a complaint letter or an email?
Both count when they reach the right team and you keep a dated copy. A letter on paper is harder to ignore than one more email in a queue. Complain.biz can push your complaint through emails, social media and paper complaint letters.
Is the letter Bizzy writes public?
No. Your complaint, in your own words, gets its own public page on Complain.biz. The formal letter stays private in your case file: you can change it, print it or save it as a PDF, or let us send it to the company.
Can I write a complaint letter to any company?
Yes. Bizzy looks the company up among the 6,013 companies on Complain.biz. Not listed yet? Tell Bizzy the name and we add the company with your complaint.