hmm if you already paid for it , the BUY button stays there , you dont actually pay for it twice... it actually tells you (after you click on buy ) that you already paid for it. instead of a BUY confirmation you get a re-instal confirmation! thats normal.
secondly its confirmed to be coming in July.
http://forums.windowscentral.com/marketplace-games/192078.htm
The Buy thing is confusing, it's one of the things I hope MS changes in Windows Phone 8.
Anyway, I hope that Episode II is a much better game, I absolutely hate the FOV in Episode 1 (game is zoomed in too much), that alone was enough for me not to buy it.
I was not confused about that, it actually did pay for it again. It said, rather than the usual "you've already paid..." that, "I'd be charged..."
The rep said that it looked like it may have been relisted, and that's why it asked for me to pay again.
EDIT: It could quite possibly have been a glitch their end. This is just a warning so others don't make the same mistake.