I tryed all that was suggested while it was suggested, it might be that the file system is behond recovery as even if I edit the card.img suggested by Nelz using khexedit suggested by towy71, I cannot find the directory with the corrupted name
the only error messages that I get while accessing the card after mounting /dev/sda1 is that the file does not exist, escaping the ? does not work (as I indicate in a previous reply)
I am very gratful for the help and suggestion, it hopened some other possibilities.
but... is there a software that can edit the filesystem (not the files) ?