To change your payment information you have to cancel your subscription. When it expires you can enter your new payment information when renewing your subscription.
You can renew your subscription by signing in with your e-mail address and your password. Then either click on your name, choose 'My BoligPortal' and click here
Or just click on ' Buy Profile' in the top rigth corner.
This will forward you to the payment page where you can enter your new payment information.