This "technical glitch" affects many new customers.
I would recommend calling Virgin customer services on 789 (free) from a Virgin mobile if you already have one. 0345 6000 789 from any other phone (standard rate call or included in any minutes) and ask them about your order.
Or if you are prepared to wait this post may get responded to by one of the Virgin team on here.
If you want to say thanks > click 'Kudos'. Answered your question? > click 'Mark as Helpful Answer' also.