Microsoft tells me my account doesn't exist!

Up until recently I've been able to use my Hotmail address to sign-in to Outlook. However, when I tried yesterday (and today) I keep getting the response that my account doesn't exist. Yet I can still receive emails (luckily, I had previously forwarded Hotmail emails to my regular email account. The Microsoft "support" site just keeps sending me in circles. I did, however, find a link that supposedly undeletes my account - perhaps I did not sign-in enough - and am awaiting their reply. In the meantime: HELP!