Something really weird is going on there with the account "Cracker06868":
https://www.megadice.com/user/182c2bd7a19e2b7573dbd1b88bc1e022He placed not much money (maybe 0.1 BTC or so) and won around 2 BTC.
EDIT:
So who is telling the truth here? Are you sure you don't have some malware or virus and someone logged into your account and went bust? I am assuming some hacker logged in, tried to withdraw the 20BTC, when it failed they got pissed and make the player lose all his money. Sounds far fetched but maybe its true.
This sounds really far fetched... I suppose that Megadice does not have the funds to pay out 20 BTC. Please look at all cold wallets they specified - they are totally empty!
EDIT2:
Now the user just won 9.264 BTC with 0.06 BTC bet.

Yes its very strange what is going on and I don't know who to believe. Those look like incredible wins.
Megadice might be inactive but they were bought out by some large whale most likely considering the Satoshidice website was very expensive. Whoever owns it probably has money coming in from other sources rather than Megadice and this business to them is most likely operating at a loss. However they most likely do have 20 BTC to cover the withdraw.
I don't understand why you would deposit 0.20 BTC and win almost 7 BTC and realise there are withdraw problems and kept gambling more and more. What is the point really? Why gamble more and more when you might not be able to make a withdraw in the first place, doesn't make sense. Most people would stop at that point.