Judging from the funds and the transaction history of that wallet, it is indeed belongs to a wallet or exchanger. The addressed isn't labelled by the wallet team on ETH and BNB chain. Still, it is easy to verify that the address is used as a hot wallet address of a platform. This is strange that 'Duelbits head support team' has done the investigation and made the decision by following the deposits which came from that address. Perhaps, they made the investigation in a hurry without giving a deeper look into the address.

Anyway, kindly upload the screenshot of the support email for clarity.