340769 CCBill Postback Missing

Someone made a CCBill payment module IPN for a clipshare installation I have, but they forgot to create a postback, causing members to stay active on my site, even after their CCBill subscription has expired. Example: User signs up for 19.95$/month using CCBill. Gets access to 'premium' clipshare package. User stays a member for 3 months and pays for access for 3 months. User then cancels his subscription. The user's 'premium' package should expire but currently, they continue to remain a premium user. I need the postback to be added so that this is fixed and so that all previous members that have expired on ccbill, are also expired on my site