Unfortunately the phone staff are not trained for anything beyond reading a script on a screen. An unusual matter like this will have them guessing any answer just to get rid of the call.
The equipment all belongs to Virginmedia and you should not tamper with it yourself. You could take a risk and do it yourself, but if anything goes wrong you will be responsible. In the worst case that might be compensation to a neighbour for their loss of service. The proper and safe way is to call for technician visits to disconnect and reconnect. That will cost £25 each time, for peace of mind.
And, of course all of the above is entirely true. Especially the call centre staff, who, to be honest, know as much about how VM’s systems work as my cat does, and my cat is actually not the brightest!
Just disconnect the cables, be careful with them and reconnect them when the work is done. Now in the unlikely event of a floating cable causing issues to neighbours, then we do need to wonder about just how resilient are VM’s systems - either way, not your problem!