If you emptied your deleted items folder in your office 365 email, you can still access the items by following these steps:

  1. Sign in to your account. 
  2. In your email folder list, right-click Deleted Items, and then click Recover deleted items.

Menu path to to access Recover deleted items dialog box in Outlook Web App

  1. Select the item you want, and then select Recover.

Outlook Web App Recover deleted items dialog box

The item will be moved to its default location. Messages will go to your Inbox, calendar items will go to your Calendar, contacts to your Contacts folder, and tasks to your Tasks folder.

*You can also purge items that are shown in the Recover deleted items box. Select the item, and then click Purge. If you purge an item, you won’t be able to use Recover deleted items to get it back. Purging a message won’t remove it from any backups that were made before you purged it.