Okex have so many features that I don't even understand how they work haha, and once my authenticator got deleted asked okex support they asked my passport ONLY no other document helped me to recover my account, I got stuck there at last I made exit
Okex is a good exchange and I used it long time ago. I didn't encounter any problem and it was a friendly exchange. But you can also use Binance the number one crypto exchange or just try bithumb global and bitcoin.com exchange, those exchange are also good to use with lower transaction fees.