I have since learned that my case is not isolated — other Rollbit users report similar treatment, where large winnings trigger sudden accusations and account freezes. Small withdrawals are allowed, but big payouts get blocked under vague “AML” or “multi-account” claims.
If privacy is not your big concern [you already did the KYC] then make the
output
input utxo of your deposit transaction. People can check the AML score and your case will have a weight otherwise it's just another random scam accusations that we always see against casinos.