@SEJ2 See post 3 in this thread. The Moderator very kindly posted you the link. There really is nothing else anyone can do for you, you have to call BT billing.
In future if you get into the same predicament, if you log onto the forum and click on your user name as shown in the following picture this will bring up a list of all your previous post and if you select one it will have the information that was previously supplied and it might save you having to ask again.