Unable to withdraw

I have done trading with Admiral Markets Global ltd.My wallet balance is $ 10696 as on date.When I was applied for withdrawal of $ 8000,the platform asked me to deposit 30% tax on total profit.I deposited tax . After that they asked to deposit conversion fees10% of withdrawal amount.Afer paying all dues the platform is not refund my withdrawal since 20 days. whenever I asked to refund they always blocking my communication and not responding properly.i have also mailed them many times but they didn't reply.