Error while restoring; backup file lost

I use Moodle 2.3.2+ (Build: 20121101).

I tried to restore a course with a backup file I made an hour before. The restore end with an error saying: error/moodle/error question answers missing in db

After that the backup file was no longer there (unfortunately I did not download the file) but also my automated backup were no longer there. The course is completely empty now, but I have I students that paid for this course.

What can I do?

Thanks, Inge