Susy has talked to ccbill. This is the answer she has got:
“CCBill accepts pre-paid cards that are issued by Visa or MasterCard. However, pre-paid cards sometimes have restrictions on how the cards may be used. Clarification on this would be best provided by having the customer contact the issuer of the card directly with any specific questions.
If a customer's pre-paid card is declined by us, they can contact our Customer Support team to see if the transaction can be pushed through manually. Many pre-paid cards used recycled numbers. This can sometimes cause fraud scrubbing systems to decline transactions. In some instances, we are able to override the decline, but it may be necessary for the customer to contact the issuer of the card.”