What's my best bet in a situation like this? The package shows delivered quite some time ago.

If it's been over 2 weeks and you've tried to contact them already then start a BTR.

How long is "quite some time"? If your trade partner has failed to respond for more than seven days, you can open up a bad trade report. You are referring to this trade, yes? It looks like you've received your end already, and so there is no loss of cards or money, you just want the trade to be done and over with so it's not hanging over your head forever, right? The deckbox team will contact the member, and if they don't respond to the report within another seven days, you will be allowed to close the trade and leave negative feedback.

Yes that is the trade. And yes I received my end. The issue I'm having is that for a few days after it was shown delivered via tracking, he continued to say he hadn't received the package.

Edit: It shows delivered on 10/22/14.

The same thing happened to me except I was on the receiving end. If you got tracking and it says delivered you don't have to worry because you are covered.

Ah, I didn't see that you had received your end. Regardless, I suggest opening a BTR so that an admin can step in to try and get the other person to communicate. If after a week the other person still doesn't respond you will be allowed to close the trade and leave feedback.

Anecdote, this happened to a friend and I. I sent him a tracked package, said it arrived, he didn't have it. He talked to the local post office, local postal carrier, magically a week later it arrived. No one ever offered any explanation of how it was scanned and marked as delivered, then showed up. Don't lose hope, the post office is shitty and sometimes things go wrong then magically fix themselves!