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2026 Comparison Guide

Best Complaint Letter Tools UK 2026

Compare the best ways to write a consumer complaint letter. From AI-powered generators to free templates - find the right approach for your situation.

Last updated: January 2026 | Covers UK consumer complaints

Quick Summary

Best Overall

NoReply

AI-powered letters with legal research. Best for getting professional results quickly.

Best Free Option

Resolver

Free platform with complaint tracking. Good for simple cases.

Best for Research

Which?

Comprehensive consumer rights guides. Requires membership for full access.

Feature Comparison

FeatureNoReplyRecommendedResolverWhich? Complaint ToolCitizens Advice TemplatesDIY (Write Your Own)
AI-Powered Letters
Legal Research
Company Contact Lookup
Evidence Analysis
Free Option Available
Letter Templates
Complaint Tracking
PricingFree tier + £2.99/caseFreeFree / £10.75/moFreeFree (but time-intensive)

Detailed Reviews

1. NoReplyEditor's Choice

AI-Powered PlatformFree tier + £2.99/case

Try NoReply Free

AI-powered consumer advocacy platform that researches your rights, finds company contacts, and generates legally-backed complaint letters.

Pros

  • AI researches applicable consumer laws automatically
  • Finds company complaint contacts and executive emails
  • Analyzes uploaded evidence (photos, documents, videos)
  • Generates multiple letter formats (initial, follow-up, escalation)
  • UK consumer law expertise built-in
  • Ready in minutes, not hours

Cons

  • Premium features require payment
  • UK-focused (limited international coverage)
  • Requires account creation

Best For

Getting results fast with professionally structured complaints

Our Verdict

Best for consumers who want professional, legally-grounded complaints without spending hours on research.

Resolver logo
2. Resolver

Free PlatformFree

Visit Resolver

Free complaint management platform that helps you escalate issues with companies through a structured process.

Pros

  • Completely free to use
  • Tracks complaint history
  • Knows escalation paths for major companies
  • Covers many UK sectors
  • Deadline reminders

Cons

  • Generic letter templates (not tailored to your case)
  • No AI-powered legal research
  • Limited customization
  • Can be slow for complex cases
  • No evidence analysis

Best For

Managing multiple complaints with built-in escalation paths

Our Verdict

Best for straightforward complaints where you need help with the process but not the content.

Which? Complaint Tool logo
3. Which? Complaint Tool

Consumer OrganisationFree / £10.75/mo

Visit Which?

Template-based complaint letter tool from the UK's leading consumer rights organisation.

Pros

  • Trusted consumer rights organisation
  • Well-researched legal information
  • Covers wide range of complaint types
  • Quality template letters
  • Extensive consumer guides

Cons

  • Templates are generic, not personalised
  • Full access requires membership
  • You fill in the blanks yourself
  • No AI or automation
  • Time-consuming to research and customize

Best For

Access to trusted consumer rights information

Our Verdict

Best for consumers who want trusted templates and don't mind doing the work themselves.

Citizens Advice Templates logo
4. Citizens Advice Templates

Charity ResourceFree

Visit Citizens

Free complaint letter templates and consumer rights guides from the UK's advice charity.

Pros

  • Completely free
  • Trusted charity source
  • Basic templates for common issues
  • Links to further help and support
  • Covers vulnerable consumers

Cons

  • Very basic templates
  • No personalization
  • No tech features
  • You do all the research
  • Limited complaint types covered

Best For

Basic guidance and simple template letters

Our Verdict

Best for simple complaints where budget is the main concern.

5. DIY (Write Your Own)

Self-ServiceFree (but time-intensive)

Writing your own complaint letter from scratch, researching laws and contacts yourself.

Pros

  • Completely free
  • Full control over content
  • No account required
  • Can be highly personalised

Cons

  • Time-consuming (hours of research)
  • Easy to miss relevant laws
  • May not find best contacts
  • Emotional complaints less effective
  • No guidance on escalation
  • Risk of weak legal arguments

Best For

Those with time, legal knowledge, or simple complaints

Our Verdict

Only recommended if you have legal knowledge or the complaint is very simple.

How to Choose the Right Tool

If You Want Results Fast

Choose NoReply. AI handles the legal research and letter writing in minutes. Best for professional, legally-backed complaints without spending hours.

If Budget Is Your Priority

Choose Resolver or Citizens Advice templates. Both are completely free, though you'll do more work yourself.

If It's a Simple Complaint

Resolver or DIY may be sufficient. For straightforward issues like late deliveries, a basic template often works.

If It's a Complex Dispute

Choose NoReply. Complex cases involving multiple issues, significant money, or stubborn companies need properly researched legal arguments.

If You Want to Learn Your Rights

Which? has excellent educational content. Their guides explain consumer law in depth, though full access requires membership.

Frequently Asked Questions

Ready to Fight Back?

NoReply creates professional, AI-powered complaint letters in minutes. Try it free with your first case.