Straight from the WHCMS EULA:
2.2 License Transfers. The Software is licensed only to You. You may not rent, lease, sub-license, sell, assign, pledge, transfer or otherwise dispose of the Software, on a temporary or permanent basis, without the prior written consent of WHMCS Limited. (For the avoidance of doubt, this license is only granted to one person or company and if more than one person or company wishes to use the Software, each user must purchase a separate license).
See:
http://www.whmcs.com/legal-agreements/I dare claim that you do not have consent to sell what you're offering. Buyer beware!
PS. You put the wrong reference in your feedback on me, but thanks for leading me to another fraudulent activity you're involved in!