in game, in the save menu for story mode or what not there is a button "open save directory" it will open the save game location in windows, there is a folder "_bin" in there is all the save game file that have been deleted, I'm not sure if there is a clean up on those files if they have been in there for a certain amount of time but your save game should still be there, just move it back to the save game root folder and there your save is back!