That crap used to happen all the time on PartyPoker to me (I know you are talking about poker stars). Once in a big multitable tournament, I was chip leader with a huge lead late in limit holdem tournament. They started having problems and after two hours of the tournament being hung, they cancelled the tournament and distributed the prize money evenly among all players live in the tournament. Man was I hacked. Then later I was in another multitable tournament but I wasn't doing as good in this one, it froze, they cancelled it and then distributed the money among all active players based on chip counts. I was like, WTF. That was the last straw, I cried to Andy about it and said I was done with that site. He recommended poker stars to me... very first tournament I played in, I took 2nd place and won $1800!

Sorry I don't have an answer for you on what will happen to your buy-in fee... I guess my point is that based on my experience (at least with a different site), anything might happen!

Good luck and sorry to hear of your trouble.