The easiest way to prevent organisations phoning you on your fixed phone number (landline) for marketing purposes is to have your preference recorded on the National Directory Database (NDD). The NDD is traditionally the tool used to produce printed telephone directories and to supply details for directory enquiry functions. You can now contact the company to which you pay telephone line rental and inform them that you want your preference not to receive marketing calls recorded on the NDD. This is a free service.
It is an offence for a person to make a marketing call to someone who has a preference not to receive marketing calls recorded in the NDD, unless the caller has some form of consent to make such calls. More detailed information on how to prevent colds calls may be found on the Comreg Consumer Website.
If you get a sales call more than 28 days after your details have been recorded in the opt-out register of the NDD, you can Make a Complaint to the Data Protection Commissioner.