SharePoint - How to Restore deleted files in SharePoint
Explains who to contact if files were accidentally deleted and need restored.
Deleted files can usually be restored for up to 93 days. Users can restore files from the site's Recycle Bin for the first 30 days. Between 31 and 93 days, they need to contact sharepointadmin@lists.siue.edu to request that files be restored. The Recycle Bin can be found on the Site Contents page.
More resources can be found on the SharePoint webpage here: http://www.siue.edu/its/sharepoint/