Need help! Repairing CR2 files!

[Lee V]

Hi, i shoot a wedding recently and downloaded all the photos (Canon raw- CR2 files) from the CF card to hard drive, all the photos have the correct file sizes and If i’m scrolling down i can see the small previews perfectly but the problem start when i open the files. 

few days after i opened the files on lightroom and all the photos from the card are corrupted! I tried open the files in alot of programs but in every program it was damaged photos. 

Since this wedding i shoot 2 other weddings so i over wrote the memory card so can’t recover from the card.

I’ve tried every program that was recommended on the web include ExiftTool, cr2 repair and Hex editor but i can’t really understand how to handle file metadata.

I read in another topic that there is a chance that the header of the file is unreadable but there is a possibility that changing the data of the file can fix the problem. !?

I’m in desperate need for help because I'm out of options and don't want to have to tell this couple I have lost their photos. anyone knows how to handle file metadata on CR2, repair CR2,  have any recommendation on what to do or can do the work? 

every success even b&w/ small jpeg or every thing that can be rescued will be helpful.