You should not link to a site your going to work on and change things on us. How are we going to figure out whats wrong with a moving target?
What I got so far:
The app isn't finished. Select ZTE or Samsung and there is no MODEL and the app shuts down.
If you pick Sony any MODEL and NETWORK does not work.
If you go back and change one of your selections all dropdown after that should disapear excect for the next one. If you cahnge the MODEL only the NETWORK select should stay showing.
And I'll not post my ideas about the database.