I'll request the TalkTalk Community team reply to you here from Monday onwards.
In the meantime, please update your Community Profile Personal Information (Click here) to include your name, current contact 'phone numbers and address with postcode (location) then scroll down to Private notes and add the email address and Save changes.
A TalkTalk OCE will reply to this thread and Community Private Message you to verify the registered email user details:
When verified, the password will be changed and one of the TalkTalk team will call on your mobile to check security with you, let you know the password and check it works. A computer generated password is not likely to be memorable so write it down carefully and store in a secure place.
Are you aware of the future migration of mailboxes to the TalkTalk Mail platform? The Mail Support Hub has more information.
You'll also wish to know about signing up to TalkTalk Mail Plus for mail users that are not currently TalkTalk broadband customers or adding the mailbox to a broadband customer MyAccount subject to not exceeding the maximum of 5 mailboxes allowed.