In many orgs three days of no email would be a serious show stopper. I dare say that if I was CTO of a company that relies on email (which is pretty much the majority of companies) I would be wary of choosing IBM for anything critical from now on.
Email broken for 3 hours is a serious incident. When everything is down, and the servers are on fire, I still expect email to work.
If they were running your systems for you, how many days would it take for you to say something in a public fashion (a tweet, for example)? Give them a week, maybe?