It's possible that VM haven't set the account up correctly so you made need to contact New accounts and Set Up for them to complete the setup and activation correctly. That would be options 1,1,1 and 4 if dialling 150 from a Virgin landline , or options 1,1,2 and 4 if dialling 0345 4541111 from any other phone.
In the meantime you could try to force the channels to update to save you calling.
Using your remote and pressing Home then Help & Settings>Help> VirginTV > go up to the top of the screen then TV Care and press OK > Missing Channels.? > Refresh my channels list
It may take 15/20 minutes to complete
The Service you do for others is the rent you pay for your room here on Earth - Muhammad Ali