Before you can get any withdrawal approved from Prolabs, you need go to My Profile and submit your MetaMask address NOTICE there is 48 hours withdraw block each time you change . This is to secure if you get hacked that you have time to contact support.
Once your Metamask address is approved, and you will withdraw, the system check if the withdrawal address matches the one you saved.
Remember the only way you can withdraw is transfer money to the exchange and withdraw from there