The best thing to do is get a fake email a fake name for that email and have it sent to your fake name at your address, and use a prepaid debit card, you can get them at walmart, pay for that with cash.
just for your information, I ordered from nirvanna a few months ago and it got searched by US customs, nothing happened, they just took the seeds and sent me the wallet that they were hidden in. They also sent a few papers saying that my parcel had been searched and that they found illegal...