Unable to withdraw normally. It said that I must pay the tax of 16500 CNY to withdraw.

I registered to trade London XAU on the platform. After that, the platform used my account for many times, which resulted in my account being locked. Then the platform staff reminded me that I must deposit gold to unlock the position, but I did not. After a few days, I found that the account could be unloaded, so I prepared to withdraw the funds after unloading, but the customer service of the platform asked me to pay taxes of 16,500 RMB before I could withdraw the funds. I was asked to deposit money before unwinding the position, and now I am still required to pay tax when I withdraw the money. In short, no money can be withdrawn.