Mark,
to CF (even if it's a short stay!)
Sounds like NTL have truly been messing you around.
Is the July 22 date in writing? If not, make sure they do confirm it.
Afaik, once you are outside your 12 month contract you can cancel with 1 months written notice regardless of any 'outstanding' bill. You can also drop your TV packages to the minimum base at any point (potentially) saving some money.
If you want to take NTL to task, do you have documented evidence of them refusing to cancel or was it just on the phone? (if on the phone, did you note dates and names)
Hope you do get sorted in 9 days.