hotmail says my account doesn’t exist but I know it does because I just used it around 6 hours ago.

I was using the hotmail email account we've had for over 10 years just over 6 hours ago. Now when we try to log in hotmail says that account doesn't exisit. I was just using it earlier today. What's weird is that our auxillary hotmail account is working but since that is not the mail account we have tied to oru business, it is not helping except for accessing the help pages. How can we get our main email account back??? Right now there are some very important emails that are flagged in that account. Can anyone please help us???  We also know that any new emails sent to our main email address, the one Microsoft Hotmail says doesn't exist, don't post. Also when I tried to set up a new email address using our supposedly non exsistant address, hotmail says it's taken. So what gives? Any help to get this back will be appreciated.