Unable to withdraw

It said that the source of my fund is unclear when I withdraw and causes the broker account being frozen, so they freeze my fund within the platform. If I want to unfreeze it, I need to send fifty thousands dollars before deadline. Otherwise, my fund will be illegal. Today, on 2/22, my platform account lost more than 400,000 US dollars inexplicably, but my platform funds were frozen on 2/17 and no more transactions were made. This is a fake transaction at all.