your story doesn't sound right or complete. best buy probably told you that you would lose the best buy student discount. that's perfectly in best buy's right to do that--and probly in their terms and conditions--because of wishy washy buyers that change their minds too often--returning products actually costs best buy money--someone has to do the job of processing returns and repacking, right?
so, in summary, you probably mis-heard best buy saying you lose their student discount as you losing both best buy and apple student discount.