I don't get that. Normal downtime is about the hardest way to fuck up email. I believe the last time my small office mail server didn't deliver legitimate mail was when I was 18 and haven't quite figured out yet what the hell was running on all these computers, and it literally ran a week with disk full.
Managed services make sense in many cases and dismissing them isn't always a good idea if that's done so easily, without further consideration.