Because they said i have 3.65 BTC there, but i must put some (little) cash to reach it....

Any service asking you make a deposit to be able to make a withdrawal is 99.99% scam.
I might probably believe it if they ask for Identification but I'll also doubt it even if they ask for identification.
Why should you believe them if they ask for identification.
If they ask you to verify your identity, it would even increase the risk of using their service. There's a big probability that they misuse your documents or sell them.