... certain that the cause was accidentally pressing the "Enter" key taking ... you think your responses were accidentally blanked out by the system ...
Uhm, check to see if you chose the reduced time option. I know I personally like to practice with the reduced time option of -3% and hope to bump it up later. . . but it sounds like you may have accidentally or forgot that you chose that option!!
I dont think you can filter for the ones you got wrong, just gotta go through the problem sets and manually check. If you deleted the pt data, i dont think you can get it back