I think you're being overly paranoid here. Package lost? Maybe. Mailman turned thief turned drug dealer? Not likely. I'm looking at both of my packages from Attitude right now; two separate packages; two separate orders ordered within 2 days of each other; and there is NOTHING on these packages that would denote they are from seed company or what they contain. My first package was a padded manilla envolope with four labels on it total; my shipping address label; an "AAX Royal Mail Postake Paid UK" sticker, an "airsure royal mail priority mail sticker (printed right on there is no signature necessary", and a lovely sticker from customs that says "Customs Declaration" with a check mark in the gift box, hand written "clothing" on the label, a total estimated value of 11 euros, and a signature from the customs agent. For my $300+ order. If customs took it; you'd receive a letter saying they took your stuff and that you can appeal (and have fun with that lol.)
The second shipment of seeds came in another manilla envelope, but this time it contained a cardboard box (got a mug on this one.) Same labels, only this time the customs agent wrote "mug/toy" on it and estimated the value at 10 euros.
Not a single marking, single label, single catch phrase, smell, odor, visual cue at all that there are seeds in there. In fact, there's not even one mention of Attitude Gifts or the company name ANYWHERE on the packaging. Why don't you call USPS and give them your tracking number; if it cleared customs you are probably pretty safe (and considering it made it to the post sorting facility, there you go.) Often times when packages are loaded on to a truck; they are entered in electronically and so there should be a record of where it is. Don't confuse USPS tracking on your end with the tracking capabilities they have on THEIR end. If you haven't already, CALL THEM (you're safe at this point; it's through customs already.) If they can't find your package, then you have your answer (an open ended answer; but an answer nonetheless.)