Exchange Online email applications stopped signing in, or keep asking for passwords? Start here.

I spent a couple of hundred dollars with a tech guy yesterday, not to mention an hour on the phone with somebody from Microsoft, both of whom had no idea why I could not get into my email account.  Why on earth would your company not send out a fix on this rather than some obscure note on the live chat request service (which I could never successfully connnect with) after the problem locked me out?  Most small businesses and individual users have a huge problem with technical terms and directions.  If you change the process of authentication, then you should make the transition something I simply need to "accept" in an update rather than be left for days being subject to futility.  This notice should have popped up immediately when I went to the help page indicating that I couldn't not sign in....Instead, everything simply said to reset my password.