Unable to Withdraw

At first someone added me through Wechat, saying that he can teach me how to do forex with a specialized team to guide me and the profit would be 5-10 times. When I tried to withdraw, they said there was a bank card error or something and I need to deposit hundreds of thousands. Later, they said my credit point was insufficient and I need to pay more. During the whole process I paid so-called taxes, risk-control fee or something, all together over 500,000.