Help with Online Payments

ISN Helpdesk – Instructions on how to solve payment issues

ISN offers two types of online payments:

  • Payments by Credit or Debit card using
  • Payments via PayPal if you have a PayPal account

Credit or Debit card payments:

    • The following cards are accepted:
      • Visa
      • Mastercard
      • American Express
      • Discover


  • Card code:
    How to find the card code (as well called CVC or card security code) on your credit card? Please find a detailed description for all 4 card types at the link below:
    Card code locations
  • General Error:
    If a so called “General Error” occurs then the credit card number, the expiration date or the card code have not been entered correctly.
  • Declined:
    If the payment transaction is declined then the bank that issued your credit card did not allow the payment. This can have differnet reasons. In 80% of the cases we find that it is either a payment limit on the card for online payments or a payment restriction for foreigen contries or both. There are many different limits/restictions that can be applied to a credit card. To find out about the limits of your credit card please contact the bank that issued your credit card and ask them to remove the limits that stopped your payment. Especiall payments to the US need to be allowed.
    Click here to get to a list of all error codes.
  • If you have any other issue with your credit card payment and your issuing bank cannot help you please contact us at

PayPal payments:

overview | print instructions