To my knowledge, it is impossible to recover data from a storage device that is unrecognizable. I would try cleaning the contacts of the card. Are they scratched or dusty? Are your computer and camera able to recognize other memory cards?
I have a card that is no longer recognized by my DSLR but works fine on my computer, which indicates that some card readers are higher quality than others (my camera reads other cards fine).
If you manage to get the card recognized but cannot see any files on it, I recommend using the open source PhotoRec (TestDisk Download - CGSecurity
) - I used it to recover many pictures and videos during a school trip to the Galapagos Islands earlier this year (several individuals accidentally formatted their memory cards).