CISAS vs Ombudsman Services: Which ADR Scheme Handles Your UK Provider?

If you have a dispute with a UK mobile or broadband provider that you cannot resolve directly, you have the right to take it — free of charge — to an independent Alternative Dispute Resolution (ADR) scheme approved by Ofcom. There are two such schemes in the UK: CISAS (the Communications and Internet Services Adjudication Scheme) and Ombudsman Services: Communications. Every provider must belong to one or the other.

Which scheme handles your complaint depends on which provider you have, not which you prefer. This guide explains who uses which scheme, how each one works, and when and how to use them.

Why Two Schemes?

Ofcom requires every communications provider to be a member of an approved ADR scheme under General Condition C5. Historically, providers picked one or the other on commercial grounds. Both are independent, both are binding on the provider if you accept the decision, and both are free to you. They are broadly similar but run by different organisations with slightly different processes.

Which Provider Uses Which Scheme?

Here is the situation as of 2026. Always double-check on your provider’s own complaints page or on Ofcom’s complaints page before filing, because providers occasionally move.

Provider	ADR Scheme
O2 (mobile)	Ombudsman Services: Communications
Virgin Media O2 (broadband, landline, TV)	Ombudsman Services: Communications
EE (mobile + broadband)	Ombudsman Services: Communications
BT (mobile + broadband + landline)	Ombudsman Services: Communications
Three	Ombudsman Services: Communications
Sky (mobile + broadband + TV)	Ombudsman Services: Communications
Plusnet	Ombudsman Services: Communications
Vodafone (mobile + broadband)	CISAS
TalkTalk	CISAS
Shell Energy Broadband	CISAS
Giffgaff	CISAS
iD Mobile	CISAS

As a rough rule of thumb: if you are with one of the big “network” brands (O2, EE, BT, Three, Sky) you will go to Ombudsman Services. If you are with Vodafone, TalkTalk, or most MVNOs (mobile virtual network operators like Giffgaff or iD), you will go to CISAS.

When Can You Go to ADR?

You can take a complaint to ADR in two circumstances:

1. After 8 weeks. If you have raised a formal complaint with your provider and they have not resolved it to your satisfaction within 8 weeks, you have an automatic right to go to ADR.
2. On receipt of a deadlock letter. If your provider sends you a written “deadlock” letter saying they will not take the complaint any further, you can go to ADR immediately, regardless of how much time has passed.

You cannot go to ADR without first raising a complaint with your provider. ADR is there to resolve unresolved disputes, not to bypass the provider’s own process.

Ombudsman Services: Communications — How It Works

Ombudsman Services is a not-for-profit company that runs several Ofcom-approved schemes, including the one for communications. Their process:

1. Submit your complaint online at ombudsman-services.org or by post.
2. Ombudsman Services notifies your provider, who gets a chance to respond.
3. A case handler reviews both sides’ evidence.
4. Mediation may be attempted first — often the provider agrees a resolution when they see the case is being investigated.
5. If mediation fails, an Ombudsman makes a final, binding decision (binding on the provider; you can accept or reject).

Timescale: most cases resolve within 6–8 weeks of filing. Complex cases can take up to 12 weeks.

Contact: Ombudsman Services: Communications, PO Box 730, Warrington WA4 6WU. Phone: 0330 440 1614.

CISAS — How It Works

CISAS (Communications and Internet Services Adjudication Scheme) is run by CEDR, the Centre for Effective Dispute Resolution, a long-established dispute resolution body. Their process:

1. Submit your complaint online at cedr.com/consumer/cisas.
2. CISAS notifies the provider, who has 21 days to submit a defence.
3. An independent adjudicator reviews both sides on the documents alone (no hearings in most cases).
4. The adjudicator makes a decision within approximately 6 weeks.
5. The decision is binding on the provider if you accept it.

Timescale: similar to Ombudsman Services — typically 6–8 weeks.

Contact: CISAS, 70 Fleet Street, London EC4Y 1EU. Phone: 020 7520 3814.

What Can Each Scheme Do for You?

Both can order the provider to:

• Credit your account or pay a refund
• Apologise (in writing)
• Correct a billing error
• Pay compensation for inconvenience (typically up to around £5,000, though higher awards are possible)
• Release you from your contract without early termination charges in certain circumstances
• Remove a negative credit marker if it was wrongly applied

What they cannot do:

• Punish the provider with a fine (that is Ofcom’s job)
• Award unlimited consequential or punitive damages
• Change the law or force the provider to change a product

How to Prepare Your Case

The key to getting a good outcome is clean, organised evidence. Before you submit:

1. Write a short, factual summary of what happened and when (no emotion, no editorialising).
2. Gather all bills, emails, SMS, screenshots, and notes of phone calls (dates, times, advisor names, reference numbers).
3. List every contact you had with the provider’s customer service and complaints team.
4. Write clearly what resolution you want: a specific refund amount, a specific contract change, a specific amount of compensation.
5. If you have the provider’s deadlock letter, attach it.

Is There a Cost?

No. Both CISAS and Ombudsman Services are free to consumers. The provider pays the case fees regardless of who wins. That funding model is deliberate: it removes any cost barrier to making a complaint, and it creates a financial incentive for providers to resolve complaints before they escalate.

What If My Provider Isn’t a Member of Either?

Every provider of a consumer communications service in the UK must be a member of one scheme or the other. If you think your provider is not, check Ofcom’s directory and report it to Ofcom — it is a licence condition.

What About Business Customers?

The Ofcom ADR requirement covers consumer and small-business accounts (broadly, up to 10 employees). If you are a larger business customer your contract typically has its own dispute resolution clauses; check the small print.

Decisions: Accept or Reject?

Both schemes’ decisions are binding on the provider if you accept them. If you reject the decision, the provider is not bound and you retain your right to pursue the matter in court. If you accept the decision, the provider must comply with it and you give up the right to sue over the same dispute. Most consumers accept ADR decisions because they are quicker, cheaper, and lower-risk than court.

Summary

CISAS and Ombudsman Services: Communications are the two Ofcom-approved, free, independent adjudication schemes that sit above your mobile, broadband, and landline provider. Which one handles your complaint depends on your provider — Vodafone and TalkTalk customers go to CISAS, most other big providers (including O2, EE, BT, Three) go to Ombudsman Services. Both are free, both are binding on the provider if you accept, and both give you a genuine route to independent adjudication when your provider refuses to put things right.