I have been caught by this too. I noticed charges for an entry on my last bill. I don't recall receiving opt out letters ..I honestly didn't know I was in any book to start with! ..I have complained and escalated the complaint So far I have been able to cancel this going forward but BT wants me to pay the £100 charges on my current bill. I am awaiting a call from the escalated, escalated complaints manager(!) Has anyone taken this to the ombudsman, and if so, have you had success? Thanks