I got fed up of the higher-ups playing favourites, and wrote a long email to the president of the place saying I will be resigning as of this Thursday. They have away a shift that should have been offered to me first -- not that I wanted it, but it's the principle of it. Wake up yesterday to an email saying that he will be gaving me more paid hours if I stay. Wake up today to a call from the manager, letting me know they talked about it and will be paying me for every time I work -- even the volunteer positions. Lesson learned.