I have to send 0.5 eth to an address to release the withdrawal.
Don't send them even a single Wei. They are proven scammers
BOT ETH ADDRESS OF THE BOT
0xe28496bCd96a0cFcDC7FDc039eEc872F6D34af77
At least they revealed something about themselves. Looks like there have been so many victims sending ETH to the address, since the round figures can clearly be seen.
The address links to Okex address for probably converting ETH to USDT, and then they send the USDT back to the address which is then sent to a centralized p2p exchange called Remitano to cash out, perhaps.
If you lost a lot of money, you can actually track those guys with the help of law enforcement, since Remitano requires KYC verification.