The dude does nothing but deliver packages all day. I'm sure he has better things to do than to:
a) Pre-memorize every single package he is going to deliver a week in advance, so that when your sister asks "when are you going to deliver the package", he does NOT have a confused look.
b) Memorize every single package he's ever delivered in the past several weeks, so he can tell you where he delivered your generic package.
c) Steal random packages in the hopes that it's something good and that he won't get caught.

If you go to the library to try check out an in-stock book, and then find that isn't on the shelf it's supposed to be, you don't turn to the librarian and say "where's the book?! Who checked it out?! You must know exactly who checked out this exact book!" and then claim that the librarian was acting fishy, and stealing books you wanted to read.

It's a misdelivered package that either your neighbor stole when it was delivered to them, or that a passerby stole when they saw the opportunity.

Yep, these kinds of things do happen. He must have delivered to the wrong address. Most parcels of significant value are insured. If they don't have the receivers signature you should he covered on one end or the other, either by the shipper who will then go after the shipping company or by the shipping company who will then do their internal investigation to determine blame and such.
I'd say be happy that the package wasn't for a ptw or nods or something lol.

My local distribution center reviewed the GPS tracker on the truck which showed him outside my house when the delivery scan was made. Also the address they had on record was correct. I'm pretty sure it was stolen by a passerby.

I get more than enough packages that my carrier has joked about it with my family members that answer the door when he arrives. I just thought it was suspicious he didn't remember this one since it would have been at least the size of a head, plus some.

I guess persistence pays off.

eBay issued me a full refund on the grounds that the seller did not provide accurate Tracking information.

The seller said he shipped registered air service which should have required a signature on delivery but Canada Post safe dropped anyway. So someone made a mistake...
either way, I'm done with this seller (bbq.bike). His communication was horrible throughout.

At least you got a resolution.

damn. that necro XD