Have mentioned this before.
Following an investigation by the FSA CPP were fined a total of £10.5m
CPP was applied to both Associates cards and later Citi branded cards.
It seems that CPP have a liability themselves for some agreements,while Citicard themselves have a Liability for others.
If you have tried seeking a refund from CPP directly,they may refer you to Citicard,who will send you a letter saying they are investigating.
I waited almost 6 months for Citicard to complete their inquiries which then saw them sending a cheque for 1 years CPP membership with no interest added.