Have you checked to make sure there is no other kind of connection? Sometimes there is no wall box, just a trailing cable. The cable could be hidden within, or behind, furniture. Occasionally only a very short stub of wire is left behind often hidden within a blanked-off fitting. A couple of past examples are below
https://community.virginmedia.com/t5/QuickStart-set-up-and/No-wall-socket/td-p/5395897
https://community.virginmedia.com/t5/QuickStart-set-up-and/No-virgin-media-wall-socket/m-p/5395697#M...
The wall box may be branded with the logos of an old cable TV company (not VM). Past occupiers of your property may have removed the cable and sometimes they are removed by other installers, such as satellite TV techs.
If you have a plastic omnibox outside on the wall (where the VM cable comes in from the street) see if you can trace any wires from that into your home.
If no luck, call the pre-installation and delivery team on 0800 052 1734 explain the problem and request a tech visit to install a socket.
VM are likely to start charging you after delivery of the kit. However, VM classifies a failed 'Quick Start' as a fault (para 6 below)
https://www.virginmedia.com/legal/fibre-optic-services-terms-conditions/automatic-compensation
You need to phone in to report the problem to VM's installation team and if VM fails to fix your 'Quick Start' problem within 2 working days your compo clock starts at £9.33 per day
https://www.virginmedia.com/help/billing-and-payments/automatic-compensation
