Sometimes smaller items might be sent in an envelope, without tracking.
I guess it depends on the price of the item. I received 2 small, untracked items from USA this way a couple of years back. There were no problems, they both arrived without any dramas.
I can't see what you bought. I tried the item number. Usually more expensive items would be sent with tracking. Within Australia, whenever I have sent a parcel, it has always come with tracking. Internationally though, not necessarily. It is a little bit more expensive to send a parcel overseas with tracking .
Hopefully though, you'll get a reply soon from your seller to let you know what is going on.
Just keep in mind that tracking is not your worry. It is the seller's worry. You have bought an item and I presume US ebay is like here, in that it will have given you an estimated date range for delivery.
That's the main thing you need to concentrate on-the delivery dates.
If the last estimated date for delivery passes and you still have not received your item, then you can open an ebay claim for item not received. You only get 30 days after that delivery date range in which to open it (or that's the case here) so keep that in mind.
