Something doesn't make sense and its dirty pool if it went off as you post--but pulling strings to get an offer pulled and induce you to take a different offer may not be illegal as such.
Now if you were a graduate of a leading MBA program I'd be suprised that you let them pull such a game even if you H-1 was the card in play!
Something doesn't right right--and I'm suprised a truly leading school would get into any such game.
But then again I went to a B school thats at top of many a list and I'd not bet the whole ranch against games--given that top schools play games as to admissions and overt price fixing as to aid packages they may play games as to exits.
The games I'm more familar with were designed to help students get better jobs--not lesser jobs! And I know of some strong arm games to help students get better jobs.