I just deposited 0.001 BTC and do same basic martingale (base bet 0.00000500 BTC) and doubled my deposit in ~400 bets (2 times 200 automatic bets and a few manual bets).
And I won 0.0011 BTC so I requested withdrawal of 0.0021 BTC and status was pending.
So I wrote in chat asking what is wait time for withdrawal to be approved and got answer that double-spending is thief and my request just canceled?! What double spending?! I just doubled money, what's wrong with it?

Deposit transaction: https://blockchain.info/tx/c95f5350c4d4bbc26ee3a43cea90e0d5ad976e8d4b6e6fed117c9499dd931f20

Screenshot gallery: https://imgur.com/a/BZ5RPpc

Deposit and withdrawal:


My betting stats:


Chat screenshot: