I think this is fair, it is good that they returned your money that you deposited, they do not have to return the profits as long as there is a dispute between you and them about these profits.

Since they returned the capital to you, this indicates goodwill by the site. According to their point of view, you violated the terms of service, so they cannot give you the profits that you obtained, and they returned the deposit to you and closed your account as a result.