There's no way to verify centralized exchange! they're not open source, not giving your seed phrase, etc. If you use centralized exchange, it's mean you're trusting your money to them and you need to accept all the risk when the exchange bankrupt, confiscate your funds, terminate your account etc and you don't have any way to recover your coins. So it's mean there's no such safe in centralized exchange!
You can't verify what is really going on inside the centralized exchanges, but you can at least peak a bit into what's going on in your own account.
For example, you can import the wallet they provide to you as a watch-only wallet. You'll see that your deposits will show up there, but then there will be withdrawals from your account that you didn't do.
And when you actually withdraw money from the service, you'll notice that it doesn't come from the watch-only wallet. It comes from someone else's wallet.
I'm not comfortable with leaving any money in a third party service like this, and no one should really.