As the code should warn, you should never use those codes after you've already played the game. It breaks it. You need to reload to a time before you put in the code.
Thank you!!! I took an autosave and replaced it into slot through appdata so I recovered my place. Do you have any advice on how to get Maria past level 29?? I have completely finished all the girls except for Autumn and the game doesnt give me an option to activate an event with her. I cant seem to figure it out.