Learning management system

I am in search of a specialized team to develop a Learning Management System for me that works both on web and mobile platforms. My LMS should have the following features - course creation and management, student enrollment and tracking, and assessment and grading. I am only looking for a one-time setup as I do not require maintenance and support services for the system. Therefore, the prospective bidder must possess the necessary expertise to deliver this solution without any ongoing support needed.