Sadly.. less than 10 days after buying it.. I dropped my new iphone 4. I have a silicon case on it which fully covers the back, but it didn't help as much as I'd hope. The touchscreen and front display is untouched and the sides are good, yet the back glass is cracked all over. Everything seems to be working, but I want to get the glass fixed if possible. Can I do that through AT&T or do I have to call apple for this? I know dropping a phone isn't covered under warrenty, so about how much should it cost for a new back plate?