Pokerstars freeroll prizes: can they do whatever they want??

[jojobinks]

a few weeks ago i finished 18th in the P* blogger championship freeroll and won a 4GB Ipod Nano. woohoo! when it came in the mail, i was a little bummed b/c they sent me a 20GB Ipod.

i'm not crying, please don't chastise me.

here's the question, though. I wanted a nano. i won a nano. they sent me a less expensive, older model.

questions:
1) can they change whatever prizes they want b/c it was a freeroll?
2) can i press the issue? how?
3) has anyone else had an experience like this? if so, how did it work out?