Hacked email account

We left virgin in May. I moved what I thought was pretty much everything over to a new email in anticipation of the virginmedia.com email address stopping. Thing is although I can no longer sign in on the virgin website the email client I use on my phone still has access to send & receive emails. 

Last night my account was hacked, I had the obligatory email with my password for my email which was correct & demanding bitcoin. They hacked my blizzard account that I haven't used since 2021 & I totally forgot I had to purchase nearly £200 of games & game points. They also hacked my discord. They managed this by getting a code sent to my email to change the address on the account. I managed to catch the code for my discord but as soon as I went to open it the email disappeared in front of my eyes & when I went to sign into discord the email.address wasn't recognised. So someone has control of my virgonmedia.com account, I know this because as I said I watched the emails in the inbox disappear & also I'm getting a lot of returned delivery failed emails so they are actively spamming people using my account.

I have contacted virginmedia 4 times now to ask for this account to be deleted. I was told the first time that actually the account doesn't exist I said well I beg to differ considering they are actively in my email changing accounts & buying stuff. He said it would have to be escalated to tier 2. The last time.i contacted I was told that an email would be sent to ask for the email address to be removed. 

People are actively hacking my email, thankfully everything is now changed, secured with authenticators where appropriate but many people are clearly being contacted via my email address & could be clicking on spyware putting them at risk.

No one seems to understand this is quite serious, an account I was told that would be deactivated a month after leaving wasn't, my details along with over 750k others were hacked thanks to a ticketing website & all I want is to try & stop someone getting spyware sent via my email by having the email deleted permanently like it should have been!!

Can anyone help at all?!

I have now gone through everything