Complaints · UK · Mobile phone
How to complain about a mobile phone network (UK)
Complain to your mobile network through its complaints code first. After 6 weeks (8 weeks for complaints before 8 April 2026), or sooner with a deadlock letter, take it to the network's free ADR scheme within 12 months. O2, Three, Vodafone, VOXI and SMARTY use CISAS; EE, giffgaff, Tesco Mobile, iD Mobile and Lebara use the Communications Ombudsman. Ofcom does not take individual complaints.
Complaint routes and time limits checked against official sources on .
First
Complain to the network
in writing
Wait
6 weeks
or a final response
Then
CISAS
free
Checked
27 Sep 2026
official sources
1. Complain to the network first
Contact customer services, then make a formal complaint following the network's complaints code. Ask for a deadlock letter if they can't agree a fix. Include: your mobile number and account number; what is wrong: signal, billing, roaming charges, contract or a network lock; dates and places the problem happened; reference numbers from earlier contacts; what you want: a refund, a credit, a repair or to leave the contract.
2. How long to wait
You can go to ADR 6 weeks after your first complaint (8 weeks for complaints raised before 8 April 2026), or sooner with a deadlock letter.
3. Escalate to CISAS
Less than 12 months after the deadlock letter. It is free. cedr-assist.com/consumer/cisas/overview
4. Escalate to Communications Ombudsman
Less than 12 months after the deadlock letter. It is free. commsombudsman.org
Who does not handle your complaint
Ofcom cannot handle individual complaints. Your network must belong to CISAS or the Communications Ombudsman.
Where to escalate and the time limits
Time limits run from the date shown in each row. Keep the final response or deadlock letter, because the ombudsman will ask for it.
| Who | Time limit | Cost |
|---|---|---|
| CISAS | Less than 12 months after the deadlock letter. | Free |
| Communications Ombudsman | Less than 12 months after the deadlock letter. | Free |
Evidence to keep
Bills with the disputed charges highlighted. Screenshots of no-signal or coverage checker results with dates. Your contract summary. Chat transcripts and emails. The deadlock letter.
Also worth knowing
ADR is open to residential customers and small businesses with up to 10 employees.
Guides and definitions
- Section 75 or chargeback: which should you use to get your money back? (Guide)
- Chargeback (A chargeback asks your card provider to reverse a debit or credit card payment under Visa, Mastercard or American Express rules, usually within about 120 days.)
- Ombudsman (An ombudsman is a free, independent body that settles complaints against companies or public bodies once the organisation has had its chance to put things right.)
- Section 75 (Section 75 of the Consumer Credit Act 1974 makes your credit card provider jointly liable with the seller for a single item costing over £100 and up to £30,000.)
- Deadlock letter (A deadlock letter is a company's written final answer to your complaint, which lets you go straight to the ombudsman instead of waiting the usual 8 weeks.)
Complaints about something else
- Energy (gas and electricity) (UK)
- Broadband, landline and pay TV (UK)
- Bank, credit card or loan (UK)
- Insurance (UK)
- Pensions (UK)
- Investments or financial advice (UK)
- Flights and airlines (UK)
- Trains (UK)
- Parcels and post (UK)
- Online shopping or a shop (UK)
- Council services (UK)
- Housing association or council housing (UK)
- Private landlord or letting agent (England) (UK)
- NHS in England (UK)
- Water (England and Wales) (UK)
All complaint guides · Get your route with dates and a letter
Common questions
How long does my mobile network have to sort out a complaint?
6 weeks from your first complaint, for complaints raised from 8 April 2026. Complain on 1 September 2026 and you can go to ADR from 13 October 2026. Ask for a deadlock letter if the network says it can do no more, and you can escalate straight away.
Which scheme handles complaints about EE or O2?
EE, giffgaff, Tesco Mobile, iD Mobile, Lebara and Lyca Mobile use the Communications Ombudsman. O2, Three, Vodafone, VOXI and SMARTY use CISAS. Both are approved by Ofcom and free for home customers.
Can I complain to Ofcom about my mobile bill?
You can report it, but Ofcom cannot handle individual complaints. It directs you to complain to the network, ask for a deadlock letter and then use the network's ADR scheme. Only the ADR scheme can look at your case and decide what the network should do.
Is there a deadline to take a mobile complaint to ADR?
Yes, less than 12 months from the deadlock letter. A letter dated 15 September 2026 means applying by 15 September 2027. Keep the letter safe, because the scheme will ask for it.
What evidence helps a mobile phone complaint?
Bills with the disputed charges marked, screenshots of no signal or coverage checker results with dates, your contract summary, chat transcripts and emails, and the deadlock letter. Note the date and place of each signal problem.
Sources and assumptions
- General routes from official sources; a scheme may ask for more before it takes your case.
- Ofcom: Making a complaint and using alternative dispute resolution (ADR) schemes (last updated 6 August 2026)
- Ofcom: Quicker complaints resolution for telecoms customers, under new Ofcom rules (8 July 2025)
- CISAS (CEDR): Communication & Internet Services Adjudication Scheme
- Communications Ombudsman: Communications Ombudsman
Guidance on where to complain, not legal advice.