Here are the steps to recover Deleted Items:
Select the Deleted Items folder then click:-Tools - Recover Deleted Items…
A window opens showing all the emails deleted from the Deleted Items folder.
Select one or more emails you want to recover, click on Recover Selected Items and they will appear back in the Deleted Items folder
You can also access the dumpster from Outlook Web Access, from the Options page:-
If mail is deleted using Shift+Del. This means emails in the Inbox is moved to the hidden dumpster.
To be able to access the entire Dumpster you need to make a Registry change.(Please take a backup of the Registory before making any change)
Click: Start - Run and type regedit then click OK to open the Registry Editor.