[Scarlett]

Make sure that you have records of everything that you have discussed with NTL to date including offers and agreements that have been made.(You could also make a data protection access request for all data the NTL have on you will cost upto £10 and take 40 Days) Write one last letter to NTL stating your case and why you believe they still owe you the money put a deadline of a couple of weeks on a response.

If they still refuse, go to regulator with the details and see if they can progress this issue.

If this fails, go back to NTL, restate your case and threaten them with court action again give them a deadline to respond.
If they still refuse to settle then start legal preceedings. You can find plenty of details on the web regarding re-claiming bank charges and this is the same process so if you look up those then you'll know what you would need to do.

Personally I would expect thatthe regulator will advise them to pay up.

On the other hand there are some VM staff on here and they might be able to step in and sort this out for you.

one last point. if they actually say tough luck, its your fault for not checking your bill then. ask them to put it in writing.