If another phone and a computer are not able to view/register the SD card or any of it's contents, it sound like it is a loss. I know of no other way to access the info.
Unless the card works, but just says there are no files on it. If that is the case, then you could try a recovery program/app and see if that lets you access any files on it. BUT the card would have to be readable for this, and most of those apps/programs have a fee.