I wouldn't talk that way about someone I had feelings for no matter how unlikely they were to see me saying it. If you have such a low opinion of her that you think she did it intentionally, or she's actually petty enough to break a device of yours over whatever (which I doubt, but I'll admit there are people like that), then it's prob'ly time to seriously consider if you actually should be in a relationship.

As for back covers, I'm pretty sure I've seen some on sale online. *Shrug*