unfortunately Virgin don't have an email address.
you could try web-chat: Help and Support - Contact Us > Mobile > Help with your mobile > Chat online.
The advisors seem always busy though so you may not get connected straight away.(If you can use a laptop, just keep the page open and refresh it every few minutes).
Or if you can borrow a phone to call Virgin Mobile. Their UK support line number is: +447953 967 967
If you want to say thanks > click 'Kudos'.Answered your question? > click 'Mark as Helpful Answer' also.