Unable to withdraw

QivuitCapital and now UGLEXCHANGE service provider. Feb 2021 I traded for 1 month CFD trading Bitcoin to US$. I had 900,000 in my account and placed a withdrawal for $40,000. I received email to say abnormal transaction and my account frozen. I was then told I could have $500,000 if I pay a deposit of $50,000. I said no way. I was told the platform needed a deposit for security. I then asked for my initial investment back of $14,000 and was declined.