My file updates were not saved to Dropbox and my computer crashed in the meantime.

Hi freixas, if you don't see any file updates on the site, and the Dropbox icon isn't visible, then it's possible that the app wasn't running, and files weren't syncing.

Do the files in Finder (since it sounds like you have a Mac device) have any sync icons on them?

i do not know the syncing status bc the icon at the top right  is nowhere to be found... and they send me some literature and could not understand what to do. i have some files synced with my computer so I do not work online. the one I lost is one.

I’m sorry to hear about this, freixas​.

Can you clarify which Dropbox platform you were using to edit your files? Was it www.dropbox.com or the desktop app on your computer? 

If you were using the desktop app, I’d like to know its current syncing status. 

Finally, since I understand you've already checked the version history of your files, I'd suggest having a look at your Events page, too (if your updates synced to our servers and your web account at any point, your Events page should show it).

Let me know what you find.