Video files from 16 Sandisk come off as large jpgs

I am hoping someone has had this issue before and knows the fix.

I shot a wedding yesterday and one of the cameras, Canon 7D using 16 Sandisk card, would not download the ceremony files this morning. Majority of the files from the card downloaded fine but the ceremony was missing.

I bought the Sandisk card reader and was able to recover a lot of the files. The ceremony portion downloads, after recovery, as LARGE jpg files but is obviously .MOV files.

Any ideas on the cause and possible conversion of the JPG to MOV?

Thanks

Paul