Make a Complaint...
Whilst I didn't want Glasonbury tickets (who in their right mind buys festival tickets with no line-up announced). I urge people to complain to the Information Commissioners office.
Companies need teaching an expensive lesson, people's data is private, and if you chose not to share it, that is the end of the story. See Tickets need taking to the cleaners.
I am personally sick of Mean Fiddler, Live Nation and Ticketmaster with their continued spam, despite never asking for it, each time I opt out, yet the cra@p continues. The unsubscribe option (naturally) does not work.