iPad mini How secure is your Smart Case?

So I have my rMini in a blue Apple Smart Case. I bought it and the rMini from another owner almost brand new (it was less than 3 weeks old). I love my case, but find that if I hold the iPad along the edge of the case, it'll easily pop the closest corner out of the case. If I flip the case all the way over the iPad falls out. It's just held kind of loosely in it. Is this the way it is supposed to be, or does this sound defective? If it's defective, is it covered under warranty if I don't have proof of receipt?

Thanks!