When you set up your account you should have been given some contributor payment options. You need to specify how you would like to be paid and if you chose/choose paypal it will ask you to verify the paypal account. It is not necessarily assumed that it is the same as your registration email.
After the recent changes to their site I believe if you have already selected paypal as your payment option and want to change that to another option, or even change the email associated with your paypal account you need to contact support to do this. I don't remember seeing any "change payment settings" since the upgrade.