My hotmail emails have disappeared from outlook account

My old emails have gone from my account, despite assurances when I logged in that all information - photos, emails, etc. would still be there after the switch from hotmail to outlook. How can I report this to Microsoft, or ask them to try and recover my old emails? Admittedly the emails are several years old, and this is an old account which I had not logged into for over a year. But I would still like to access my old emails and I don't see why, if my account is still accessible (it is), my emails should not still be there. I did not give permission for these emails to be deleted. There are now ZERO emails in my account. Could someone please tell me how I can contact Outlook for a response/recovery????