We learned the lesson, and never again trusted Dropbox, for anything.
(Best guess - a would-be client got pissed when software which they'd never paid for lacked a feature, and told Dropbox a story.)
EDIT: Only executables & related distribution files were on Dropbox, not any source code. We lost nothing...except our trust in Dropbox.
EDIT2: Yes, as several others have kinda pointed out, this incident was a collision between (a) naive human expectations (of high-skill, high-touch, highly-invested customer service for such situations) and (b) the actual business model of any huge / cheap or free / convenient cloud provider of X (plus just "internet reality"). Sadly, I don't see that either (a) or (b) has changed in the past decade.