Hello!
I believe I can help you with your case design. I have 18+ years of experience with CAD / CAM software, and i´m a Computer Graphics teacher at Senac High School.
To your project become true, i´ll need some more info about the model you want, such as the phone model, how do you think the opening / closing device would work, etc.
To my proposal, i´ll provide you all the sides 2D blueprints (front. hear, top, bottom, left side, right side), plus a series of 3D images demonstrating the parts and how the final product would look like.