Don't believe a word of what they told you on the phone support line. Yes, the email account is a free add on provided by VM to their broadband customers who signed up prior to May 2022, however once the account is closed the email address is deleted. Sometimes it goes on beyond the 90 days stated in the T&Cs but you can't rely on that.
There is an outside chance that a process called Move and Transfer could be used to move the email addresses from the old account to the new account. However the criteria are tight and usually require the old and new accounts to be in the same customer name.
The VM Forum Team should be able to advise further.