Complaining to an ISP is one of life’s more frustrating experiences. The default response to almost any complaint is a scripted series of line tests, router restarts, and polite non-resolutions that eventually run out of energy.
But the process doesn’t have to end there. If you approach a complaint correctly — with the right evidence, through the right channels, at the right time — you have real options. Here’s how.
Step 1: Know what you’re entitled to
Before you complain, know what you’re actually owed. The key documents are:
- Your contract. Find the section on Minimum Guaranteed Speed. This is a legal obligation, not a target.
- Ofcom’s code of practice. Ofcom publishes guidance on what ISPs must provide and what redress you’re entitled to when they don’t.
- Your provider’s complaint procedure. All ISPs are required to publish this. It tells you who to contact and what the escalation path is.
Step 2: Build your evidence
This is the most important step, and the one most people skip. Without evidence, your complaint is your word against the ISP’s diagnostic systems — and those systems are designed by the ISP.
Good evidence includes:
- Timestamped speed test results — ideally from an automated system running continuously, not just a few manual tests
- Latency and packet loss data — these often show problems that a speed test alone won’t catch
- A log of when problems occurred — dates, times, duration
- Records of previous contacts with your ISP — dates, reference numbers, what was said
The difference between a complaint that goes nowhere and one that gets results is almost always the quality of the evidence behind it.
Step 3: Make a formal complaint
Contact your ISP through their official complaints channel — not just customer service. There’s a difference. Ask to log a “formal complaint” and get a reference number. This starts the 8-week clock that matters for escalation.
In writing, clearly state:
- What’s wrong
- When it started
- What it’s affecting
- What evidence you have
- What you want (a fix, compensation, or permission to exit your contract)
Keep the tone factual. Attach your evidence. Send it by email so you have a written record.
Step 4: Escalate if nothing changes
If your ISP hasn’t resolved the complaint within 8 weeks — or issues a “deadlock” letter saying they can’t take it further — you can escalate to an independent Alternative Dispute Resolution (ADR) scheme at no cost to you.
There are two ADR schemes for UK broadband:
- CISAS (Communications and Internet Services Adjudication Scheme)
- Ombudsman Services: Communications
Your ISP is a member of one of them (they’re legally required to be). The ADR scheme will review your evidence and the ISP’s response and make a binding decision.
With solid evidence, ADR escalation often results in compensation, bill credits, or permission to exit your contract penalty-free.
Step 5: If all else fails, switch
If you have a strong evidence base showing your service hasn’t met the contractual minimum for 30 or more days, you’re entitled to exit your contract early without paying termination charges. Use your evidence to make that case in writing.
Before switching, research infrastructure. If you’re on FTTC (fibre to the cabinet, which is actually partly copper), a move to full-fibre FTTP will likely solve speed problems regardless of provider. If you’re already on full-fibre and still seeing issues, the problem may be the provider’s backhaul network — and a different ISP on the same infrastructure might fix it.
The single most useful thing you can do right now
Start monitoring your connection automatically. Not because you expect a problem, but because if a problem does emerge, you’ll already have months of data showing your connection’s baseline performance and exactly when things started going wrong.
That evidence base is what separates a complaint that gets resolved from one that goes in circles.