@John_B2021please for your own sanity do not have even the slightest hope that somehow VM will come up with a solution for you to keep the mailbox without being a customer. The Virgin Group might well be the most innovative, far sighted and availed company on the planet (hint : they aren’t) but as @ravenstar68 says, that’s all irrelevant as the Virgin Group and Branson have absolutely nothing to do with VM (other than letting them use their brand) - VM is a wholly owned subsidiary of an American company called Liberty Global, who when they say jump, the board of VM reply in unison’ yes sir, how high exactly sir’.
Even if the marketing people though your idea had merit, it would require new billing, customer services and accounting procedures to be put in place, there would be technical issues to address and change - it is all geared up for email addresses to be tied to live broadband accounts, that would all need to be unpicked.
Short answer, it’s just not going to happen.
Getting a relative in a VM area to sign up, probably won’t work either. I believe for a move and transfer to take place (as the process is called), the old email address needs to be associated with an account - which yours being orphaned, won’t be. Again it’s a procedural thing, there just isn’t a mechanism to do it.
Lastly, you can setup forwarders on your old address but these would be associated with the mailbox itself, once the mailbox is finally deleted, the forwarder would go with it, so this is a strictly short term method just to get you enough time to notify all of your contacts that your email address has changed.
I’m sorry to say that this email address absolutely will vanish, could be later today, could be a couple of months but it is on borrowed time.
John