How to Complain to CISAS
CISAS settles disputes with phone and broadband providers such as O2, Sky, Three, TalkTalk, Virgin Media and Vodafone, once the provider has had 6 weeks to put things right. It is free. Complain to your provider in writing first, and we print it and post it for you by Royal Mail.
Not complained to your provider yet? Send your complaint by Royal Mail Tracked 24, from £8.99, so you can prove the date it arrived.
From £2.49 including printing and postage
- No printer or Post Office trip
- See the finished letter before you pay
- Order by 2.30pm for same-day posting
Quick Answer
- Complain first to
- Your provider
- The provider has
- 6 weeks
- Then you have
- 12 months
- Cost
- Free
- Phone
- 020 7520 3814
A deadlock letter from your provider lets you go sooner. For complaints made before 8 April 2026, the wait is 8 weeks.
Where to Send It
Complain to your phone or broadband provider first. If it does not sort it out, apply to CISAS online, by email or by post.
Your phone or broadband provider
Your complaint to your provider, which comes first.
The address on your billor your provider's complaints pageSay what went wrong and what you want your provider to do, and keep a copy.
Write your complaint letterCISAS
Posting your CISAS application form.
CISASCEDR100 St Paul's ChurchyardLondonEC4M 8BUUse the April 2026 application form from the CEDR website. No printer? Fill it in, save it as a PDF and upload it, and we print it and post it. You can also email it to cisas@cedr.com.
Write to this addressIf your provider uses the Communications Ombudsman
BT, EE, Plusnet, giffgaff, Tesco Mobile, iD Mobile and some others use the Communications Ombudsman instead.
Communications Ombudsmana different free schemeOur Communications Ombudsman guide explains how to complain, including by post.
Read the Communications Ombudsman guideChecked against the CISAS rules and the CEDR and Ofcom websites on 19 October 2026.
Why Send It With PostRight
Proof It Arrived
Choose Tracked 24 and you can see when your letter was delivered, with a photo on delivery. Useful when a deadline or reply time counts from the day it arrives.
No Printer, Envelope or Stamp
Type your letter or upload a PDF on any device. We print it, put it in the envelope and post it.
Posted Today
Order by 2.30pm on a working day and we post it the same day by Royal Mail.
The Address Done for You
Press Write to this address and we fill in the address exactly as it is shown on this page.
How It Works
- 1Complain to your providerWrite to your provider, say what went wrong and what you want it to do, and keep a copy.
- 2Apply to CISASAfter 6 weeks, or once you have a deadlock letter, fill in the April 2026 CISAS form. Upload it as a PDF and we print it and post it to CISAS.
- 3We print it and post itOrder by 2.30pm on a working day and we post it the same day by Royal Mail. Choose a tracked service for a record of when it arrived.
Complain to Your Provider First
CISAS only looks at a dispute once your provider has had the chance to sort it out. For complaints made on or after 8 April 2026, your provider has 6 weeks. For complaints made before then, it has 8 weeks. If your provider sends you a deadlock letter, saying it will not do any more, you can go to CISAS straight away.
Put your complaint in writing and keep a copy. A tracked letter shows the date it arrived, which helps you count the 6 weeks.
How to Apply by Post
CISAS takes applications online, by email or by post. To apply by post, fill in the CISAS application form dated April 2026 from the CEDR website and post it to CISAS at 100 St Paul's Churchyard, London, EC4M 8BU. Older copies of the form still say 8 weeks, so use the April 2026 version.
No printer? Save the filled-in form as a PDF, upload it, and we print it and post it for you by Royal Mail.
Which Providers It Covers
Ofcom lists NOW, O2, Sky, SMARTY, TalkTalk, Three, Virgin Media, Vodafone and VOXI as using CISAS. BT, EE, Plusnet and Tesco Mobile use the Communications Ombudsman instead. If your provider is not on either list, Ofcom suggests checking with the schemes directly.
Time Limit
You must apply to CISAS within 12 months of your provider's deadlock letter.
What Happens Next
An independent adjudicator decides your case. The decision only binds your provider if you accept it within 30 working days. Your provider then has 20 working days to carry it out. The most CISAS can award is £10,000, including VAT.
Other Ombudsman Guides
Frequently Asked Questions
CISAS, CEDR, 100 St Paul's Churchyard, London, EC4M 8BU. You can also apply online or by email to cisas@cedr.com.
Send your complaint to your provider today.
Write or upload your letter, choose your service at checkout, and we print it and post it by Royal Mail.