For those with a grievance against TalkTalk, we've listed everything you need to know below to get your complaint heard and resolved, including social media pages and chief executive details.
For complaints about your TV, landline or broadband service call 0345 172 0088. You can also use TalkTalk's live online chat function to send a complaint.
Alternatively you can write to TalkTalk (TTR), PO Box 675, Salford, M5 0NL. It says it tries to reply to every postal complaint within 10 days of receipt.
In the email or letter include your name, the date the problem occurred, your TalkTalk home telephone number, the names of any customer service advisers or managers you may have dealt with and a description of your complaint.
It used to be worthwhile sending a letter to the CEO marked "private and confidential", but this isn't as effective as it used to be now that so many people use it.
However, you can try to get the company to escalate your complaint to the chief executive's office by writing to Head of Complaints – CEO's Office, TalkTalk (CEO), PO Box 672, Salford, M5 0NG.
Complaining on social media can be extremely effective. On Twitter you can contact @TalkTalk – copy @MoneyTelegraph into your tweets so we are aware of your problem.
Alternatively, post on TalkTalk's Facebook page.
If your complaint hasn't been resolved within eight weeks, or you’re not happy with the outcome, you can make a formal complaint to CISAS, an Ofcom approved dispute resolution scheme.
This is a free, impartial service for communications consumers. It will investigate customer complaints and its decision is binding, so TalkTalk would have to pay up if it found in your favour.
Call: 0207 520 3814, email cisas@cedr.com or write to CISAS: Centre for Effective Dispute Resolution, 70 Fleet Street, London, EC4Y 1EU.