Signed up to Volt but how do I get the O2 sim?

I've just signed up to Volt, received my Virgin box and set everything up fine, but have received nothing about my O2 sim. There was an email from O2  that had a verification link, but it was only valid for a week and I didn't see it in time, and I can find no way to get another link sent or find a way of getting the sim that I'm now paying for. Can someone please help?