My hotmail account was switched to Outlook, once I was allowed to log in all of my emails were completely gone! How can I retrieve them? Who should I contact to help fix this problem?

my hotmail account was transitioned into an Outlook account a few weeks ago, I never got any email notification. I hadn’t logged into my hotmail account in 3-4 days and when I did it told me it was Outlook.com now, i wasn’t able to long in for days because it kept showing an "error" message. when I finally got in all my emails for the past 6 years are completely gone!! how do I get them back? i did not even think this was possible and I am really upset and confused. I did not rename my account or make any changes. Please let me know how I can retrieve my emails that were deleted against my knowledge (I already tried to restore them with no luck) or who I should contact to help with this issue. thank you