Whatever, they surely would have been said that I could withdraw only with BTC. It's pointless to play here if they use fiat currencies (USD/EUR) as balance , but only cryptos are allowed to deposit because you lose huge amount on unfair converts. Support said : "there will be BTC/ETH etc like you said before, but later."
The volatility of Bitcoin is very high. Maybe they send your Bitcoin in equivalent to your fiat balance minus the fee then the price got correct by the time you receive it. If you can track the time of your withdrawal request, You can verify the actual price of Bitcoin at that particular moment to backup your claim. And also about your complaint about deposit currency. I believe it was stated on there ToS before you sign up.