The problem here is that if your MiL isn’t a current VM broadband customer, then the only thing that the forum team here can do is to arrange for the email address and mailbox to be fully deleted. At some point she must have had access to a legacy NTL broadband account to get the address, once this terminated, then the email should have been ended some 90 days afterwards. In practice this doesn’t always happen promptly and they can linger on in a sort of zombie state. But are always liable to be deleted without further warning at any time.
It is very likely that her email hasn’t actually been hacked, but rather she used the same password on another site, sometime in the past which has been. Imagine, for example that ‘Fred Bloggs Hardware’s’ site gets hacked and the hacker gets away with a load of email addresses on passwords used on that site - knowing that, alas, people still tend to use the same password on many sites, they take a punt and email everyone on the stolen list and as, ‘I know your password is xyz’, so pay me money or else!
Like I said, if she isn’t a customer, VM won’t help to change the password and allow her to continue using the email address, at best they will offer to delete it. So what I strongly suggest is that you create a new email address for her with another provider; both Microsoft and Google offer free .outlook.com and .gmail.com addresses. Having done that, if she is still able to send and receive emails from her existing ntlworld.com address, then she starts the process of going through all of her contacts and informing them of her new address, to be used in the future.
Then she can request VM to delete the old mailbox entirely, which is likely to happen at some point anyway.
