Indiscriminately operating the client's lock position when the market fluctuates violently, resulting in huge losses.

I was in a lock position, and the funds in my account at that time were as shown in the picture below. They secretly operated seven of my short orders at the top of the market, leaving long orders. In the end, there was more than 1,000 US dollars left in the account, and the customer service actually said it was because the margin was insufficient. What does Lock position have to do with margin?