iPhone 4s need advice.

I am looking for some advice regarding a genius bar appointment i have tomorrow. A couple months back i took my phone into the apple store to have it checked out because it was not working properly with my pioneer AppRadio. The video display was all different Colors(Rainbows). It used to work great then all of a sudden it started acting up. I educated the genius that my Fiancés iPhone 4 works just fine with the radio as mine used too. He did some tests and stated that the radio must be defective. I had the stereo store check it out and they verified the radio is fine. Now today i got a Mophie juice pack plus for my phone. It will not work with my phone at all. It will not charge the phone or allow me to sync the phone. However it does work with my fiancés phone. I feel there is something wrong with my Phone. It is like the dock connector is defective. However it looks fine. How do i get the genius to understand whats going on and replace it? it is still under the 1yr warranty.

I would really appreciate any help you guys could give me.
Thanks in advance
Joshua

Here is a link to the Juice Pack Plus.

Yes i have checked compatibility. The app radio is up to date. So is the iPhone ios 5.1.1. I think i am just looking more for a way to convince the Genius at the Apple store that the phone is having an issue.

Thanks