How do I contact a moderator?
Post what your problem is and if a moderator can help they will reply on your post.
EDIT: If it is about your problem here: https://community.bt.com/t5/Bills-Packages/Charged-for-TV-amp-Entertainment-not-had-since-May/m-p/24...
the moderators do not have account access so they will most likely not be able to help other than to refer you to the Customer Service department which has been mentioned in your post.