You are wise to ask. Opening any attachment, like a pdf, can install a virus.
Also, something may pretend to be a pdf, but actually be something more dangerous
So even if genuine, it is a stupid way to send out unexpected information. Virgin should not be telling their customers to open unexpected attachments.
One sign of a bad email , is that it does not include your actual name, something that virgin know but scammers may not.
While you wait for a response, it should be safe to save, not open, the pdf file and then scan it with whatever internet security you have. Usually a right mouse click brings up a menu where you may have a scan this with xxxxxx option
What is the name on the file that someone wants you to open
I'm going to be more direct. This is a scam. The format of the e-mail address in the body text is quite different from what I would expect to see from VM. Just delete it and forget about it.
Superuser 2017/18 Use Kudos to say thanks Mark answer as "helpful" only when the problem is solved Please don't send me private messages unless I ask you to. I do not work for VM. The advice I give is based on my best understanding of VM policy and practice. You rely on it at your own risk.