xbox 360

I just received my xbox 360 back from wherever microsoft has them fixed at ! yeah ! but boy am I still pissed ! apparently they dont give you your unit back ,they give you a different one , not a new one ! refurbished ! thats fine ,it still has mine and my sons gamer profile and all our acheivements on it but , you can no longer save a game on it ! my poor son after playing lego star wars for an hour or so lost all his progress due to this problem ! he'is pissed off ! so am I , if I have to send it back they better give me more than 1 free month of xbox live or I may have to switch to a ps3 !!!