Folders turned to file - all files from them lost

Here is what's happened: usb drive (FAT32) got pulled from Mac w/o eject. 2 folders became 0byte files. Miraculously, no errors in FAT!!! And that is the problem!

File recovery soft (CnW fully licensed, ZAR demo, Recuva demo etc) caot find them folders and their files, like they were never there! There are no traces of them, nothing in deleted files either (I guess b/c they were not deleted per se but somehow became forgotten).

Anybody has an advice?

Thanks.