a cracked LCD on the Iphone cannot be replaced by any ordinary LCD.
as the LCD has to be able to cope with all the motion sensors and touch functionality.

Send it back to Maxis and they're gonna quote you around RM900 and give you a new Iphone no matter what excuse you give.
Don't bother repairing it tho, the price is gonna end up around the same, so why not get a new Iphone.