You don't receive mining results on the website wallet (you only make an account to buy miners), it goes to your miner username. You use a bitcoin address as username, where the funds will be sent. You can use even an exchange deposit address (if the exchange allows those small transactions).

It's best that you mine to your own wallet. Sites sometimes go down. Other people sometimes teal other people's money. Why would you risk this?

What is your miner username?