Hello MtQn_17, welcome to the community and thanks for starting your own thread. We will try to help, but need to establish a few facts first.
Do a test on mailtester.com to see if the address might be still in existence, although this is not always proof of anything.
Do you still have a VM broadband account? If so is this ntlworld address showing when you sign in to My Virginmedia / my profile or manage accounts?
I am guessing the answer is NO, you are not a broadband customer, and therefore, VM should have deleted the ntlworld account 90 days after you ceased to be a customer. So the news may not be good and there may be nothing that can be done. Those other accounts that use the deleted address WILL have other ways to recover your access. Contact their customer service to find out what they require.
If you are a customer, and your email is not attached to the account, let us know and we'll adviser further if there is a chance to recover it.