Wait! How do you know they just can't afford you, maybe need you to work less? If you were fired, I think they wouldn't have bothered with asking you to call the manager (and I don't think they would fire you with her on vacation), I think they may just not have enough hours for you or something. Do call the manager and get a good reference if that's the case so you can get another job, quicker (hopefully with a store that needs someone more hours and can afford it).