Our database host messed up their maintenance

"When you do your post-mortem, focus on actionable outcomes rather than placing blame. Because ultimately anyone can screw up at any time."

I disagree with this. You need to place some sort of blame and focus on actionable outcomes.

Anyone can make this mistake, but with important data, there are some people that really shouldn't be handling it and they need to know why, which is where the blame comes in. This is the only way to resolve the issue.

Your host warranted (maybe or maybe not in the legal sense, but still) that their personnel were competent to perform the work you paid them to do. But that turned out not to be the case. That is the real problem.