It dropped flat on its back and as it landed I was like, whew it would be safe...after picking it up the back is completely shattered. The phone works flawlessly however when I hold it I get shards of glass in my hand. Where to buy a replacement? I recently took a friends iPhone 4 in for the same reason while I was at the store and they replaced it for no charge. I may go in but it's such a hassle as I could just buy one and change it out myself.