my uploaded content
Your uploads don't appear to contain any useful data. The ones I looked at are composed of only image files.
It could be that the site requires 3D data to be included before the items appear in a library search.
GrabCAD is about CAD data, 3D models. The images are great to show what the model is, but nobody can make use of an image file of a phone. They need the 3D data.