Customer Is Always Right?!

Everything fell apart last two days. One of the big customers system decided to fall apart on the week of my company's user conference. The user conference basically gave a chance for our customers to meet with each other and the executives. So the system picked the perfect time to fall apart. The management was freaking out when they heard how bad the situation was. The customers were not happy we didn't keep them up to date on the progress. Though we fixed up their database, they demanded an answer why this happen in the first place. Since they are one of our big customers and it would make us look extremely bad if they talked to other customers (especially we are announcing a new release). With my manager not around, I became the point person in development to deal with the issue. I know it is urgent, but there is only as fast the developer can work on the issue, especially a random goose chase. If the customers could give us more information, it may be easier to trace back how all these happen. But since they don't even remember, the developers could just speculate what happen. I have been running around between floors to find out answers. If I kept this job and things still this crazy, I may not need more exerecise.