Hide the EPP code if an invoice is due. This feature is important since I have lost a handful of customers because they have 'stolen' the EPP code from our system while they didn't paid for the hosting, nor anything else. While hosting isn't *really* important, an unique domain can be. By having the ability to keep a clients domain to yourself until they have paid, it could dramatically reduce the amount of fraud.
Please add this feature to WHMCS!