If you need to contact Virgin before your welcome pack arrives to discuss account they can ask you two questions about the account rather than the password to verify you are the account holder. They will be able to find the account with your postcode.
As for your Tel number dial a mobile from the landline and the number will show up.
Has this post helped you out? say thanks by clicking on the Kudos Star. I work for Virgin Media - but all opinions posted here are my own