Try connecting the phone to a computer via USB cord and then access the SD cards data that way.
If it is accessible at all, you should be able to copy it to the internal storage of the phone or to the computer from there. You should also be able to delete what you want from the card.
NOTE: If this is a card that was set up to be "Internal" storage for a device (that one or another one) the data on it may not be accessible.