Your original post is still there;
https://community.virginmedia.com/discussions/email/e-mail-hack/5612012
I do agree though that sometimes a post appears to go missing only to reappear later, and I can fully understand why you might think it had somehow gone and hence start a new one.
To answer your questions, although VM do have some UK based support staff, there is no ‘special number’ or trick to guarantee getting through to them. It’s all a matter of pot-luck and since the bulk of support is offshore it is very likely that you will be put through to them. There used to be a school of thought that calling just after 8am would increase your chances of getting a UK-based person. But recent posts on here suggest that this is no longer the case.
Of course, 'your mileage may vary’, so you might want to try it and see.
If, as you say, a third party gained (temporary) control of your email account, then who knows what they may have done with it, what they may have deleted or what their motivations might be. But VM don’t keep backups of your mailbox data, no more than the Royal Mail keep copies of every letter you sent or received, or who those letters were addressed to; just in case. The onus to keep copies is on you. So, if contacts and/or contents of folders have indeed been deleted and you don’t have copies then, alas they are gone.