I have had several friends order from them with no problem at all. However, my first order with them didn't make it to me either and I ordered about the same time you did.
From what I read, often you will not even get a letter. Could be due to them being stolen anywhere along the line, customs might just be taking their sweet time processing everything or they could have honestly been lost.
Regardless, it's a risk when you order them, you know this and you can't really be upset with Nirvana because of this. How do you expect them to stop customs? I'd love to hear your ideas on that one. It happens and it's a risk you decide to take when ordering from any vendor.
The simple fact that Nirvana is even willing to replace the order should speak for itself. They don't have to...They could just tell you that your SOL and I doubt it would hurt their business. Yet, they care enough to replace your order. Yeah, horrible company to do business with. Gimme a fucking break.
I'd be willing to put money on the line that both orders were sent and just ended up getting nabbed by customs or someone else along the way. Have you really ever just sat back and thought about how the whole process works?
..."I reject your reality and substitute my own." <---hahaha, best quote ever!