If a person makes a coin deposit to their Zloadr “wallet” the deposit goes to an ETH address that only Zloadr has the private key to. You don’t even own your own wallet private keys.
Obviously, you really don't own the address they generated to you.
As far as what I understand, the airdrops rewards go directly to the app.
Now, if you want to check the validity of those rewards, transfer your airdrop rewards to your own address, if possible
(as you stated exchange never worked).