There was a problem with registration yesterday and before which has supposedly been fixed. NTL installers do just that, set up the stb or cable modem the rest is your job. Perhaps he should known there have been ongoing problems and advised you accordingly that there are problems registering.
Mind you don't get too excited we still can't access e-mail for over a week now, and can't access our account, hopefully NTL staff will sort all these ongoing problems out.