1. Here is the help page on how to regain control and hopefully secure your network and account.
https://www.virginmedia.com/help/virgin-media-mail-my-email-has-been-hacked
2. Agree, no one is making you use the address. Once you have control, start migrating all your connections to another email provider (preferably not with any ISP) that has better security to match what you are using it for, and better support and spam filtering, too. Set up forwarding to catch anything you miss. Don't use the out of office notice. Turn off the spam filter - let the new provider catch the spam. After backing up anything you want from the mailbox, delete all information from the emails and contacts so that no one can use the data if it is hacked again.
~ ~ ~ ~ ~ ~ ~ ~ *\o/* ~ ~ ~ ~ ~ ~ ~ *\o/* ~ ~ ~ ~ ~ ~ ~ ~ *\o/* ~ ~ ~ ~ ~ ~ ~ *\o/* ~ ~ ~ ~ ~ ~ ~ ~
I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more
Have I helped? Click Mark as Helpful Answer or use Kudos to say thanks