Unable to withdraw money, scam broker

I deposited $5,000 here and after a while, I wanted to withdraw some of the money but they said my account was suspected of money laundering and requested to deposit an additional $4,200 for verification. If I do not make this deposit, my account will be frozen and I lose all original funds. Why is it so absurd? They said, I made too few transactions, but actually, I entered a lot of small deals everyday. My withdrawal was pending for 8 days and then the result is an unreasonable rejection.