Wait a second. If you jump on him now for the fake tracking number, you won't ever hear from him again and you certainly won't get your $13 back. And even though it's unlikely you'll get it back anyway, why not give him a chance to back out gracefully if that means getting your $13 back?
Just remind him that you both agreed you would pay upon delivery, and you will do so. You could even say that you understand shipping takes some time and when it arrives, you will pay right away. Since you know nothing has been shipped, this puts him in a corner. All he can do is continue to pester you for payment before (as far as he knows) you discover there is no shipment.
If he "cancels" his "shipment", you can be understanding and say that's OK, just refund the $13 you paid for shipping. If that doesn't work, THEN you can blast him with the fake tracking number and make all the noise you want.
But I think if you let him know of the fake tracking number now, you'll never get the $13.