This form will automatically generate a DPA Section 11 'No Marketing' letter for you to send to your Internet Service Provider. This letter prohibits the ISP from using your personal data for marketing purposes. Don't worry, you don't need to know your ISP's data controller details, its all automatic.
To quote ICO; "You should keep a copy of the notice you send and the reply you receive from the data controller, and all other communications, recording the dates of all correspondence. This will be important as evidence in any future consideration by the Commissioner or the court."
Simply select your ISP, enter your account reference, name, address, click submit... and click print to create the letter. All you need is a stamp and an envelope.