Vencent Freelancing Service — Fraud

I join vencent freelancing service
They told me to fill online form
They provide 650 form and time interval is 7 days
I am starting working but in 5 day the server is blocked for that they charge rs 7999 and told me it is refundable with salary but after completing my project they told me your accuracy is not 90% so you again pay 3999
But when i realise it is fraud company
I complaint and told him to give my amount they use abuse language and b lock me