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Join Which? MoneyBank complaint delays warning as AI 'makes up fake laws' – should you use it?
Ombudsman warns that incoherent chatbot submissions are slowing it down
Faye was Headline Money Consumer Money Journalist of 2023 and a Wincott Award finalist in 2025. She's been investigating scams for nearly a decade.
If you're thinking about using artificial intelligence (AI) to help you write a complaint about your bank, insurer or another financial firm, make sure you check the facts before hitting send.
The Financial Ombudsman Service (FOS) says that AI-generated complaints – often containing fake laws and rulings, and misquoting existing laws – are increasingly causing delays.
If you need to complain about a firm, you can do it yourself for free, and AI can help you when used wisely – but you still need to do your homework. Read on to learn how.
What does the FOS do?
If you're unhappy with how your bank, insurer or another financial firm has handled your complaint, you can take your case to the FOS – a free, independent service that settles disputes between consumers and financial firms.
Common complaint issues include customer service problems, denied fraud refunds and insurance claim delays.
You must normally exhaust the firm's internal complaints procedure before going to the Ombudsman. Complaints can be made for free online by filling in a web form or by phone. You may need to submit evidence supporting your claim.
It's not necessary to use a claims management company (CMC) or a solicitor to bring your complaint, and doing so is likely to incur fees.
The FOS will review the evidence provided by both sides and give a written decision about what's fair. It can order firms to compensate customers who it decides haven't been treated fairly.
- Find out more: how to take a complaint to the Financial Ombudsman Service
How is AI affecting complaints?
In a blog post from March, chief operating officer Marc Harris sounded the alarm over delays caused by complainants' 'excessive or uncritical use' of AI.
He said that in a sample of recent complaints, up to a third appeared to be 'generated or heavily assisted' by AI, with some demanding 'significant caseworker time' to verify their contents, delaying outcomes for everyone.
In extreme cases, claims management companies and solicitors are charging consumers fees to represent them, but using AI to generate excessively long submissions littered with 'errors or misunderstandings'.
Some responses exceeded 200 pages in response to a six-page provisional decision.
The FOS said firms were also seeing similar trends. While this is 'not yet a major operational issue for the sector', it's described as an 'emerging risk' that 'warrants coordinated attention'.
However, Harris also said that AI could help people explain their complaints more clearly and make support easier to access when used appropriately, particularly for some vulnerable and neurodivergent consumers.
Should I use AI to complain?
When used properly, chatbots such as ChatGPT, Claude and Gemini can help you articulate your argument to a firm or ombudsman in a clear, concise way.
However, they are no substitute for knowledge and research, because of their tendency to hallucinate (make up false information).
Before using AI to draft a complaint, you should use reputable sources to gain a clear understanding of what your rights are as a consumer, and where you think the firm has fallen short. You can use our range of money and consumer rights guides to do this.
Once you understand your rights, you can use that knowledge to write a detailed chatbot prompt. For example: 'Write a complaint to the UK's Financial Ombudsman Service saying that my bank has broken the PSR rules on mandatory reimbursement by refusing to refund me after I was a victim of fraud.'
In your prompt, you will usually also need to supply the chatbot with an overview of your case and a timeline of the key events.
Check the AI-generated text carefully for factual accuracy, length and tone, and make any desired edits before submitting it to a firm, ombudsman or redress scheme.
Alternatively, consider using one of our template letters to take the hard work out of writing a complaint.
