Dont know what has changed in the recent few weeks but i personally have withdrawn around 1.8 btc from freebitco i love the site its fun and profitable however the past few weeks i have done nothing but lose literally every stratagy i used to build up my 1.8 has left my balance 0.00000000 :-( ive lost around 0.3 now sure it could just be bad luck but it feels like its on purpose i even put it on 1.01 and lost loads of rolls like wtf is going on dont think its worth the multiply game something has defo changed stick to the free rolls people :-) or lose everything u have
To be frank i am really surprised to see someone win this big with the rolls in the site as i have not heard about this from anyone,you are just a lucky individual to win this big as the house edge they have is much bigger than rest of the traditional dice sites and be happy with what you have fun and take a break before loosing everything back. 
I do not think that you need to be surprise to have this kind od player on their site. You can check their lottery system which give us more than 3 btc as the total prize so you can predict how much wagered on their hi-lo games. I believe they are getting more than 3 btc as their profit just to give us this huge amount of prize. I do win once but not that much so I do not think it is impossible to win on such huge house edge site