I currently own one and if you want to zoom just slide your finger on the left of the screen. You'll see that the bar comes up for you to do so.
Also, this is my 2nd N8, my first one was defective and I sent it back so there's a great possibility that yours may be too.
As for bad quality, are you sure that you're shooting at 12MP?
Also, take a read....China have a friggin CLONE oui!
http://nokian8portal.com/exclusive-chin ... id-2-1-os/