Hi callanml31
Have you tried signing into https://www.virginmedia.com/my-virgin-media/ and clicking on "Upgrade package"? This may show you online offers currently available to yourself, or a link to a chat box to discuss a new package/contract.
You can also try the following cancellation page if you'd rather take that route.
https://www.virginmedia.com/help/leaving
Either scroll to the bottom and click on "No I need more help" which opens another window and click on "Chat to us online", or click on the "I want to cancel" box situated in the "How to cancel your Virgin Media contract" sub section. This will open a pop up window, so ensure you have pop ups enabled in your browser. Then click on "Chat to us online".
The chat options won't work if the office is closed, so best to try during normal office hours