Don't worry, I'll keep paying the full price to subsidise you grabbing freeloaders!
...but when my 12 months are up, I'll be ringing up like the rest of you
This is a crazy situation though. Usually, by the time retentions speak to a customer, they have already chosen their new ISP, taken a 12-month contract, set up direct debits etc. Many of them can't be persuaded to stay at this point, whatever the deal.
NTL need to discount heavily or they'll lose much more money in lost customers.