Many companies today work with "Microsoft 365" and therefore with Outlook, Teams, OneDrive, SharePoint, M-365 groups, etc.
All these applications are cloud-based and the data is stored on "some" Microsoft server "somewhere"! It is often difficult to understand where your own data is backed up. Especially when companies work with OneDrive and/or Sharepoint shares and/or share data in Teams or Office 365 groups. Unfortunately, where many hands (or mice) are involved, mistakes can easily happen, and not always in such a way that you notice the error straight away.