Virgin Media needs a separate cable. They will only fit one if it's economic for them to do so, and physical problems are sometimes found once they get on site to do the installation. Sometimes that involves getting permission from local authorities which can take weeks.
And yes in cases like this their customer communication is awful.
Welcome to the Community Forums, thank you for taking the time to post here.
I am very sorry to hear of the poor and confusing experience you have had since signing up to our services. I would like to look into this further with you via PM so I can understand where we are up to with the progress of your installation and the reasonings for the delays.
Please look out for my PM over at the purple envelope.