<human>: Can you give me a shortened version of the text?

A graduate program contacted me with an offer of admission, stating that I had been accepted and that I should be very proud of myself.  I was sent a digital invitation, carrying the signatures of the dean of graduate affairs and the dean of the accepting school.

I was very excited (this school was my top choice) so I accepted the offer, told my friends, and declined other offers on this information.  

Several days later, I received an email stating that this offer was in error and that I should disregard it.  After speaking with the graduate office, I was told that this had never happened before and that it was very embarrassing for them, but you aren't allowed to come, sorry.

What do I do?
<bot>: I was accepted, then unaccepted.  Can a university do this?  Is it worth my time to press this issue with legal council, or will it just make my life more miserable?