As a company policy, we do not provide partial refunds for unused credits (unless of course, a system malfunction caused the problem).
We reserve the right to shut down campaigns at any time if we feel that you are abusing our system in any way. Be sure to read and understand our terms of use before using MailChimp. If we determine that you have abused the system in any way, and we shut down your account, we do not provide refunds for unused credits.