[MovedGoalPosts]

You can tell your bank at any time that a Direct Debit mandate is cancelled. Your bank must accept that instruction.

---------- Post added at 17:49 ---------- Previous post was at 17:26 ----------

You asked me via PM what would happen if you did the above. I'm replying here as it's a view that everyone ought to be able to see and make their own contribution:

Ntl might come after you by other means, if the DD is cancelled, debt collectors that sort of stuff. At least cancelling the DD stops ntl trying to take money from your bank account and stops the bank charging you every time they try.

At the same time as cancelling the direct debit, write to ntl (use the billing address), preferably by recorded delivery so they can't deny not getting it confirming the cancellation and that the contract ended on xyz date.

The next bit might or might not work. Otheres have suggested that the contract rolls on until you the customer tell ntl that it's cancelled. That is normally the case, and the ide of a 9 rather than 12 month contract period normally refers to this as being a minimum service period. You could try playing the laymans card thinking that 9 months was your contract - it might or might not work. Whatever the result on that, despite ntl failing to bill, and failing to attempt (to your knowledge) to collect at the time (monthly) the service charges, they were and are still payable for the 9 month mimumum contract so I'd prepare to cough up.