Blockchain.com wallet was compromised and btc stelon I lost some money in a ico scam and googled and found a reclainfund ltd to recover fund. They ask me to  set up a blockchain.com account and then share account wallet id and password so they can transfer stolen fund. I did that. then I transferred 0.51 btc to my account and then changed my password.  now it seems to be hacked and my btc is gone and all transaction history is gone.  The weird thing is the blockchain's account left panel is totally empty now once I login and I can't see any transactions. how could that happen ? I wonder if someone inside blockchain.com is associated with hacker or scammer. that is really some high level scam I have ever see.
my question is in my blockchain.com account, where is the private key that they can steal and copy and it can bypass my changed password ?
They only needed to have access to your account a single time to have exported your private key, then that wallet is compromised for good. Your password encrypts the private key as stored on Blockchain.com's server (so that Blockchain.com can't read the key) but it doesn't change the private key itself.