How Can I Get the Diploma?

I need some help. I've had the 'Cartomagia del Bolsillo' course for three years now and I want the diploma, but I'm not sure how to get it without watching all the videos. Since I'm a professional magician, I only focus on what's useful for my routine. On top of that, even when I watch some videos all the way through, they aren't marked as completed.