Every month you receive and email with your monthly bill.
Access to this email where you will find a link.
1) Click on the link to go to your Payment account (Monsum).
2) Go to your Monsum Customer Dashboard (right side of your company Name).
3) Click on Edit Data.
4) Here you can change the payment method.
For further assistance about your payment method, send an email to firstname.lastname@example.org