Had daily call from Liverpool based PPI
Called me at least once a day for over a month until I got fed up at their failure to remove me. Eventually I just went along with what they were saying to establish the company name and looked them up on due-dil. Managed to find their finance director and from that a quick google found me his home number.
Called him on a Saturday with my mobile number to let him know for every call I received from his company I would call him twice. Hung up. And called him straight back to ask how annoying it was. Seemed to work as I haven't heard from them since.