The site's down. Quick, Tell the customers

I used to work in telecoms about eight years, and loved one of our SMS providers, simply because they'd send an email the instant an issue was detected on their end. This helped us, in turn, to communicate with our customers, and also not waste time investigating why messages weren't being received at whoever's end.

Compared to another supplier we were hooked up to, who quite often we'd be the ones informing their support staff that there was an issue. Utterly frustrating, and self-defeating as it meant we'd sell towards to the former provider whenever possible just for the fewer headaches alone.