You're looking at the folder where the executable is located. You need to go to:
C:\Users\[USERNAME]\AppData\Local\UnrealBoxing\Saved\SaveGames
Change [USERNAME] with your Windows username. There, you'll see files like CustomBoxer_01.sav, CustomBoxer_v02.sav, or CharacterCutomization.sav. Delete them all (you'll lose your character's customization).