Issue Linking Virgin Media Account to Virgin Media O2 ID Account.

Below taken from a previous discussion on this forum but as it's the exact same issue and they explained it well I've stolen it. 

Hi all - hoping posting here can shed some light on this whole process. I am a new customer with virgin media, and have just been sent all the emails through with my contract etc. on the email address I used to set up the account. The emails said to set up the My Virgin Media account, so I clicked the link and registered my Virgin Media O2 ID account. It then said to link that account to my Virgin Media account, however when I did so, it said that the email accounts don’t match, even though I used the same email address for both:

“We’ve found your Virgin Media account

However, this account is linked to an email address that’s different to the one on your Virgin Media O2 ID.

If you’d like to continue and link your Virgin Media account to your Virgin Media O2 ID, please confirm the full email address your Virgin Media account is currently registered to.

We’ll then send an email to that email address to approve the transfer.”

So I put my email in (the one from which I received all emails about my contract setup), but it is saying the email address doesn’t match even though I literally copy pasted it from my contract document. It gave me five attempts to put my email in and the same error message came up each time - I now have one attempt left and don’t want to use it in case my account gets blocked. Please could anyone advise on what I’m doing wrong or if this is a glitch or something?? It’s a bit of a niche problem I think, and I couldn’t find anything on the FAQs! I feel like I’m going insane because I’ve checked the email so many times to make sure there are no typos or anything but it’s still not working!