A week ago loads of empty folders I have on Dropbox were deleted. Initially I spent loads of time looking at them and restoring them, Dropbox then deleted the ones I had restored. Now I waste no time and I restore the empty folders and Dropbox then deletes them a day or so later. It is happening so fast that it cannot be a human but I don't know how to stop Dropbox deleting the folders I want - even if they are currently empty