Self installs are only offered if there has been a service in use at the property in the last few years.
The sockets are VM property & should not be removed, however if the previous occupant was not a Virgin customer or was & then changed provider they may have removed it.
Check on you outside wall for an omni-box which terminates the cable from the street. If this is also missing it gets even more complicated as a repull back to the street cabinet will be required, causing further delays. Omni-boxes are usually brown (as below) but older ones may be grey.
Virgin brown omnibox
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