vicodin

Just for clarification, it isn't the only item in my inventory. I keep 25+ items on hand at one time.

Are you sure you aren't just extremely unlucky?  You said you cancelled the lot, which I'm assuming means you left the stamp in your inventory while Abrosia was running.  It is completely possible a random event caused the item to disappear and it did not show up on the log (which happens to me occasionally).

I've considered that possibility. But the same exact item twice? I'm not sure what the odds of that are but I'm assuming it's incredibly small...

Is the account one you purchased? I've heard of people selling accounts and still accessing them after they are sold. Some people don't secure the password and email after purchasing because 1) They are too trusting. 2) They don't want to draw attention from TNT. 

No it's my own account. I don't share it with anyone so I'm the only one who knows the password. After my last stamp disappeared I actually ended up changing the password and checking the email. The email is still my email and even after the password was changed... the item disappears again.

Maybe someone else got access to your shell? Or TNT is stealing them, for some reason, but of course TNT would just ban you instead of silently taking them away.

I don't see how they would. I only use the account to AB so I don't really visit any other pages (no chances to be CGed). I've also ABed items worth more/around the same and yet those stamps have stayed for weeks. It's just this ONE particular item that seems to be disappearing.

Thanks for all of the advice! I'll be sure to take all of this into consideration. What is this impending Neopets doom you speak of though? It's been a while since I've actively played Neopets but I don't see many differences between now and 2008?

Can TNT track your IP? If I want to make a shell account should I try only logging into this shell from a different computer/location?