What's my username/password?
On the Apple device where the account was created, go through the motions of purchasing a membership. When purchasing any product the app will show an error alert (pop-up message) displaying the ChessKid username originally connected to your Apple ID.
If the above doesn't work, click on the "sign up" button, create a new account, and then try purchasing a membership once again. This should also cause a pop-up to appear with the username linked to your original Apple ID.
Once you have your ChessKid username, email our support team at firstname.lastname@example.org for assistance in changing your password.