you'll get a hub3 as a replacement, so if that doesn't meet your requirements then put it into modem mode and buy your own router that does meet them...
how do you know it's not a line issue? and thus replacing the hub would make no difference?
also, don't make threats of leaving. if you're going to leave just leave. virgin doesn't provide DSL so not sure what you're relying on for you job, but if you need a business level SLA then you need to pay for one. this is a home package.
***** If you think my answer has helped - please provide me with a Kudos rating and mark as Helpful Answer!! I do not work for Virgin Media - all opinions expressed are of my own and all answers are provided from my own and past experiences. Office 365, Dynamics CRM and Cloud Computing Jedi
Oh and if you want to whinge about terminology (pedants)....go ahead. It doesn't matter about the delivery medium or signalling - DOCSIS / Cable - DSL / twisted pair. What matters is the fact that it's seemingly impossible to get a response from the ISP to assist.