Hello. I have a Pen drive that i need to recover some Excel files, those files are very important.

I have been using Recover My Files, Recover4all Pro, he can recover the files, ... well... almost, the program can see the Excel files, and even recover, but when i try to open one of them, they don't contain data, or the file gets wierd, my something like a code.
What program could i use, to recover files with out them get corrupetd?

Thanks