I had the same problem when I clicked cancel at the save dialog instead of save Anyway this was years ago and I managed to get the recording back by first securing the aud and grf files, opening a new file and then switching over the new aud file with the recovered aud file. similarly with the grf.
This worked kinda ok. As I remember, the pitch was messed up quite badly but was still ok because it was just speech.
I tried this again today, out of necessity and Im finding that i cannot switch round the files because a dialog pops up to say that they are in use. Renaming or replacing the files wont work either because they are in use.
I still cant remember how i did this exactly last time but ill let you guys know when i figure it out.