Yep - just received an email confirming that's the case. The costs are not made clear up-front. I would have expected to be able to cancel with a click, but no, you have to downloaded a form I and send to them in Switzerland - or mercifully there is an email address. Feel like a right scam. Very disappointed than National Rail should have anything to do with such a dubious outfit.Just be careful that if thud is an offer from completesavings.co.uk (which you can get when you look up train times on national rail and get forwarded to a vendor) that you follow to the letter the terms and conditions.
Otherwise you will have signed up to a £15 monthly direct debit until you cancel.