Also happened to me and I discovered that just selecting Cancel does not cancel, in fact you have to do this 4 times. Each time the next one is out of the visible page on the screen so you have to scroll down, particularly underhand when you have completed a short survey asking the reason for the cancellation after just the first time of selecting cancel so you are led to believe it has already been done. These companies all follow a similar pattern and phone numbers are non existent, they don't want you to contact them!
These sort of practices are completely underhand and you should only have to do this once and you should be able to clearly see all the information in a single page. I've written to OFCOM to report this behaviour and you should do the same. It's unlikely they'll refund your money until you have gone through the whole thing as they can say you did not complete the process fully. You need to check the pass you have cancelled is now showing as 'restart'.
