Ofcom-regulated provider
Three must comply with Ofcom General Conditions including complaints handling requirements and ADR access.
Communications Act 2003; Ofcom General Condition C4
Three not helping?
Keep proof of poor coverage claims and billing.
Content is for general information only — confirm deadlines with regulators and ombudsmen.
Your rights
Key protections that often apply in this sector. Always check the latest official guidance.
CISAS ADR route
Three uses CISAS for eligible deadlocked complaints. Free for consumers. Submit after 8 weeks or a deadlock letter.
Ofcom General Condition C5
Roaming and bill limit protections
Ofcom requires providers to set financial limits on data use when roaming outside the UK and send alerts as usage approaches the cap. If Three failed to do this and you received a large roaming bill, this supports your complaint.
Ofcom General Conditions
Consumer Rights Act
Three's mobile and broadband services must be provided with reasonable care and skill and match descriptions given at sign-up.
Consumer Rights Act 2015
Escalation timeline
Typical stages for UK consumer complaints in this sector.
- 1
Formal complaint to Three
Contact Three through their complaints channels. Get a reference number. For coverage issues, note your postcode and specific locations where service fails — this helps if you need to argue the coverage checker was inaccurate.
Ofcom General Condition C4 - 2
Written follow-up
If not resolved, send written evidence: billing screenshots, coverage checker results vs actual experience, speed tests, and correspondence.
- 3
Deadlock or 8 weeks
Request a deadlock letter or wait for 8 weeks from your formal complaint.
Within about 8 weeksOfcom General Condition C5 - 4
Submit to CISAS
File online at CISAS. Free for consumers. Binding on Three if you accept the decision.
CISAS scheme rules
Common issues
Coverage gaps
Poor signal in areas shown as covered on Three's coverage checker, dropped calls, and inability to use data services in everyday locations.
5G and 4G speed issues
Speeds significantly below marketing claims, inconsistent performance, and congestion during peak hours.
Roaming charges
Unexpected bills when travelling, add-ons not working as expected, and charges for data used in countries that should have been included.
Billing and plan disputes
Charges not matching the agreed plan, confusion about data limits, and unexpected costs after promotional periods end.
Credit check refusals
Being refused a contract without clear explanation and impact on credit score from multiple applications.
Customer service
Difficulty reaching support, long wait times, and complaints being closed without proper resolution.
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Suggestions are for guidance only. Always verify with official sources.
Frequently asked questions
What if Three's coverage checker was wrong?▼
Take screenshots of the coverage checker showing what was promised for your area, then document actual experience (dropped calls, no data). This evidence supports a complaint about being sold a service based on inaccurate coverage information.
Can I leave Three for poor coverage?▼
If coverage at your home or workplace is significantly worse than the coverage checker suggested at sign-up, you may have grounds to exit under the Consumer Rights Act or Three's own returns policy within the initial cooling-off period.
Roaming bill shock?▼
Ofcom requires bill caps and usage alerts when roaming. If Three failed to send alerts or apply the cap, raise this in your complaint. Check whether an add-on was active and what it covered.
What is CISAS?▼
CISAS is the independent ADR scheme Three belongs to. It is free for consumers and handles deadlocked telecoms complaints.
Does CISAS charge me?▼
No. Free for consumers.
5G speed complaints?▼
If Three marketed 5G speeds you are not receiving, document the difference between advertised and actual speeds with tests. Raise a formal complaint.
Can I switch while complaining?▼
Yes. Use a PAC code to keep your number. Your complaint rights continue.
What evidence helps?▼
Coverage checker screenshots, speed tests, billing documents, call/data logs, and all correspondence.
Related pages
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