Induce fraud and unable to withdraw

I met someone via Wechat and started to trade XAU future to Feb. 11, 2022 on the MT5 platform of Rui Win Capital through him. The total of my profit and principle are $233902. On 2-11-2022, I want to withdraw $30000, but I was informed that I need to pay 20% tax of total profit and it cannot deduct from the balance. They locked my account without any fomral notice. I tried to communicate with customer service, but there was no response for several days. Hence, I suspect that this broker is a fraud group.