trading in phones with att?

I currently have the Samsung Galaxy Note 2. It's a good phone but it just has too many little bugs that samsung needs to clean up. I've noticed it in my girlfriends s3 too. the build quality isnt too good either. I babied my note 2 since the day I got. It has never touched the ground, never been bumped, scratched, bent or been through any abuse, but somehow the plastic back cover got some weird cracks. You cant really feel them or see them, but I know they are there. they're almost like pressure cracks. it just looks like a spider on the back of my phone but its barely visible. I took it to the att store and they told me that it's normal wear and tear (girlfriend and best friend having same problem). I like the phone but I dont at the same time. is there a way I can trade in my phone at the att store for another phone? maybe put some cash up along with the trade in? I've had the iphone plenty of times and I really like the feel of a solid phone. I like the weight and the organization. Has anyone done this before? did you have to hassel them about it?