Tracking is only useful to the seller.
Go to the eBay Resolution Centre and open an Item Not Received Dispute. Escalate it as soon as possible.
Generally the GSP does not cause any unusual delay. And those tracking numbers seem to be internal to Pitney Bowes. They may actually be invoice numbers for all we know.
Under a corollary of Murphy's Law, complaining about a missing parcel, should cause it to miraculously appear. Just posing this question may have put this Law Of Nature into play. Quick! Go check the mailbox!
The numbers you have been given do confirm that the GSP recieved the item and it is on its way to you. While the Dispute won't help with delivery, it will get you a refund.
Note that it is not the seller's fault that PB/GSP did not deliver promptly.
If the item arrives after you get the refund, you can refund it through PP's Send Money. But I have no idea who you would send the new payment to.