Turn Email Box Off, messages deleted from server?

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If you previously set up an email account for someone ([email protected]) with a mailbox and a redirect but then turn the email box off, only keeping the redirect on, does "Bob's" email get deleted from the server at that moment? - Thanks

 

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I found you have to delete the account then reset it up again to empty the email box. If you simply turn the mailbox off, it stores the email for that user.