Hi, I dropped my white iphone 3g on the pavement today. Figures the one time I dont have a case on my phone I drop it. Anyways, there are 2 small chips that I dont really care about but on the top left by the power button there is a small chunk taken out with a few dark spots in the chunk. Is there a way to replace the back plastic piece? I cant imagine it being that expensive if you do it yourself. I had an appointment for a genius to look at my iphone for battery issue and was hoping that they would give me a new one. Would me dropping it ruin my chances of getting a replacement phone? Also, I heard that you are able to exchange your phone at the AT&T store for a different color would the damage prevent me from exchanging it.