Is Dropbox a backup service? Nope.
Dropbox is folder synch, a network version of a pendrive. Dropbox makes no guarantees about the durability of the data on their servers, which are merely a browsable cache.
Use proper backup services, instead, like Memopal.
Storage isn't backup. If you have one copy of your files ("home") then you have zero copies of your data. You're only one hiccup away from losing it all, as this person found out.
Use proper backup services, instead, like Memopal.