Welcome to the community and thanks for posting. Sorry to hear you're having difficulties accessing your voicemal.
I've had a check and it looks as though voicemail is not currently setup on your account. So I can get this sorted for you I will send you a private message shortly (purple envelope, top right hand side).
Welcome to the Community, I'm sorry to learn about the inconvenience you've experienced in trying to get your Voicemail active.
I've been able to locate your account and can see that you've not got Voicemail set up on your account. I'd recommend giving our team a call on 150 from any Virgin line or 0345 454 1111 from any other and we'll get this set up in no time.