Nokia 6300 help needed Please

It seems that my 5 day old Nokia 6300 has a slight problem...

Down the side of the phone, where the aluminium metal joins the black plastic, there is a slit, where they seem to have seperated slightly. It is about 1mm in diameter, and is easily viewable when the KeyPad lights are on, then you can see the light shining out. on the other side, it is perfectly fine.

I hadn't noticed this until I bought a "Crystal Hard Case" from TMobile. After about 30minutes of it being on, I picked it up to inspect it, and noticed the fault in the phone.

Im not sure weather it is to do with the case pulling it, or a manufacturing default.

If anyone could offer me any guidance to any possible cure/fix, or any other things that I could do to fix this fault, I would be very thankful.

Thanks very much,
Regards
Sivad

exchange it for a new one