For payment processing via payment system providers (e.g. PayPal), only the terms and conditions of that payment system provider apply. in addition, the user may need to have an account with that provider. The payment process may also be offered, supported and simplified by other service providers that provide what is known as “single sign-on solutions”.</p> <p>(9) After a purchase, the user can receive a receipt for the ordered services in electronic format to the e-mail address provided by him.</p> <p>