Unfortunately, it is exchange services like
https://changelly.com/ that encourage these platforms to continue operating and thus scam investors.
HitBtc are selective scammers and therefore they will deal with you, create an account, trade until you deposit a huge sums, and then you will come to the office and the arguments in order to steal your money.
I am sorry for your loss, but I think you lost twice, the first with money (2.3 BTC) and the second by sending the documents as they might have sold them.
Yeah if you never do a lot of value they are fine.
25 USD worth of coin zero issues.
Most every thread that says they are a scam is over 1000 usd worth of coin.
Does not matter what coin.
people still use them because at first they don't ask for kyc.
So they move a little coin here and there with no issues. Then they up the deposit and get hammered.