In order to recover files deleted from your account by mistake, it ought to be enough just to fill out the form that you will see when you go to https://portal.metu.edu.tr/odtu_bidb/yedekleme/yedekleme.xhtml address and choose the date and folder that you want to recover. The system backs up the files in your account every night. You can recover the files that have arrived before back-up time and the files which have been deleted after back-up time.
Note: Backup copies are kept for 30 days.