Is it permissible to take the remaining cost of the course and use it for self-education and launching projects, instead of completing the course with the institute?

You must explain the reality of this course to your employer and that you did not benefit from it, and the decision is theirs. It is not permissible to cancel the course and take its value for yourself without the knowledge and permission of your employer, because an agent is not allowed to act except within the limits of what their principal has authorized them to do.