New Customer - Cannot create My Virgin Media Account

I'm a new Virgin Media customer and have received emails regarding my contract details, sent to the email address I used to set up my account. The instructions said to create a My Virgin Media account by registering a Virgin Media O2 ID account, which I did. However, when I attempted to link my newly created Virgin Media O2 ID to my Virgin Media account, I ran into an error stating:

"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."

I copied and pasted the email address from my contract documentation to ensure accuracy, but despite confirming multiple times, the system still rejects it, claiming the addresses don't match.

I can provide screenshots if required.