Hi Jan,
I understand that you want to recover some deleted items.
First please check if these items are stored in Deleted Items folder, if not, you can follow the steps below.
You can recover Deleted Items in Outlook Web App (OWA) referring to this link.
help.outlook.com/.../ms.exch.owap.recoverdeleteditems.aspx
If you’ve configured your account in Outlook client, you can also perform this action in Outlook.
If you’re using Outlook 2010, please follow these steps.
1. Locate the Folder tab, and click Recover Deleted Items on the menu bar.
2. Select the items that you want to recover, then click the Recover Selected Items button.
Thanks,
Young Yang