The email is being used to create the account and cannot be modified.
Once you log in, click on the top right circle and choose Account Settings.
Some profile information like email associated with your paypal cannot be modified. If you really need to modify these kinds of information, please contact us directly.
You can modify your password in the Account Settings.
Have you entered the correct username or email when logging into your account? If you have and you are still unable to access your account, have you tried resetting your password? If not, we recommend doing so first.
If you have already done this and are still unable to access your account, we recommend reaching our to our Support team. They will be able to take a close look into your account to see if there's any restriction preventing you from accessing your account.