Wonder who is telling the truth here.

So you deposited 0.2 BTC and managed to turn this into almost 20 BTC, which is incredible performance. I am assuming you took huge risks to maintain these large wins.

This site is fairly inactive so they have a small hot wallet which is usually empty, you made a deposit of 0.20 BTC and won some money and were only able to withdraw 0.20 BTC which is pretty much your deposit.

Then the admin finally refilled the hot wallet from the cold wallet so you could make your withdraw however certain strange events happened,

The admin claims that while they were refilling the hot wallet, you kept gambling and lost all your money.
While you claim that you didn't do anything and when you logged in your balance was almost 0.

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.