Is Henfin safe?

In this May, I was pulled into a stock group, in which teacher gave some stock recommendations. I also bought some stocks recommended and profited a little. I trusted him gradually. Sometimes I listened the livestreaming as well. Then he advised us to trade digital currency since the stock market was volatile. We trusted him a lot in wake of former profits. He recommended such products as OKB and CCMT of Jingui Exchange, claimed at least a 3 fold profits after they were listed. I gave OKB a shoot and profited a little. He also encouraged us to add fund, saying that a large deposit could increase the winning percentage. Many members sent their deposit screenshots in the group. I also joined and deposited all my savings these years, 500 thousand yuan, 300 thousand of which was used to buy OKB and CCMT. Since under finance crunch, I withdrew the 20 thousand, but faced a series of problems. The teacher and the platform kept holding off, asking me to deposit all fund. At that time, I didn’t feel it was a legit platform. As card-to-card transfer, why the withdrawal is so difficult?