Aw man, that really sucks! I really hope you can get this straightened out.

I know how you feel, I got screwed too recently when I bought a Nokia Cell phone. The one I received was defective, and when I returned it they told me : damage due to water, so sorry, no warranty.
This was a BRAND new phone. It turned out that one of their employees switched the PCB board of the phone with a defective one. (so their technical report was correct : this PCB DID have water damage, it just wasn't the PCB out of MY phone!) I was able to proove this with the serial number. But even then they didn't believe me. The treatment I got was, to say the least, very rude.

To top it all off I found out that the defective switched PCB I got was a PCB out of a stolen Nokia phone.

I finally was able to solve it because I pulled a few strings, but needless to say I'll never frequent that store again. I'll might even go as far as contacting a consumer organisation or my local DA. I'm not sure about that yet.