What John_GS was asking was if you are accessing your VM emails via a web browser, or a third party application such as Outlook or the built in email application on Apple or Android devices.
The web browser route gives you a direct ‘view’ as to what VM currently hold in your email mailbox, if this is the case and the send items are missing, then, I’m afraid they are gone. I wouldn’t like to speculate as to the underlaying cause, but VM don’t keep backups and hence there is nothing that they can restore - in fact they make it clear in the Ts&Cs that the onus for keeping backups is with you, the customer.
