Today my Hotmail page has been replaced by 'outlook Mail (Preview) '. All the folders I created in Hotmail are missing with the emails they had in them. I did not instigate this change and would like my Hotmail back.
Have you tried logging in direct to Outlook.com, in your browser? The name changed from Hotmail quite a while ago (About 2years, I think) But for you, it is only a name change.
How did you originally access your account?
As far as I am aware, the preview you see is merely a new app introduced by MS for Office365. You are not obliged to use it. But a user may be able to confirm that.