If you are using web mail stop worrying. The letter suggests settings for e-mail clients which from the limited amount you say you are not using.. What you must do is change your password and security questions in My Virginmedia. If you are using a macmail client the settings are there.
Superuser 2017/18 Use Kudos to say thanks Mark answer as "helpful" only when the problem is solved Please don't send me private messages unless I ask you to. I do not work for VM. The advice I give is based on my best understanding of VM policy and practice. You rely on it at your own risk.