Cracking after a month? That's rough, especially with that model work throwing all sorts of abuse at it... I bet it's the material not holding up to repeated impacts or maybe even the way it fits the phone, causing stress points which, yeah happens more than you'd think with inexpensive stuff.
I've switched to tougher designs that wrap around better and it made a difference, no more constant worries. If budget's tight, hunt for deals on sites with good return policies. Anyway, hope you find something that sticks around longer this time.
