Please don't ever give up trying to get through to them. Tell them what you have tried and put the ball in their court. NTL have always been good at CS in my opinion and I can appreciate your frustraition as I work as an adviser for another ISP. If your config is fine then it must be net related, provided you have checked for spyware etc (Which you have). Just hang in there and I am sure you will get a result.
(Excuse the cr4p, just got in from a night out of winding the Scots up about the world cup).
No offence to the Scots that frequent this forum...
