So when i motion tracked a text and placed it into the scene it was good but when I apply element plugin to the text layer the text dissapers from the screen and when I press scene setup in element plugin it says no model now what do I do.
I'll just reiterate the comments above, you're simply using Element 3D incorrectly. Follow the instructions in ShiverCactus's post, or follow Mylenium's advice and do some tutorials on using the plugin. Once you get your head around how it works it's actually quite straightforward.
I suggest you actually study the video tutorials over at VC. This is not how the plug-in works. E3D must be applied to a solid covering the entire comp and the text referenced in its layer slots. Again, seriously watch the tutorials.