Do you mean you use your hotmail e-mail addresses as your login name for all your MSC accounts? I do also. If hotmail is down, it should not affect your ability to get into your MSC accounts. Or do you use your hotmail e-mail to click on a link to access your MSC accounts? Can you google the MSC to get to your account - for example, Intellishop shopper login?
I'm not understanding why you need to get into your hotmail e-mail account to file a report with an MSC.
I have 4 hotmail accounts for different things and have logged into all 4 this morning with no problems.