Unable withdraw money? Am I being scammed?

I was introduced to MT5 by an acquaintance and traded at GSM Securities and made a profit, so I thought about withdrawing money, but I was told that a security deposit was required, and I paid 7228 usd, but the money was not transferred.There are other people who are also playing MT5, but I was told that I would not pay the deposit, is this a scam?