No idea what you mean by his shop showing items again, a filtered search of his listings indicates the most recent offering was posted back in November of '19. As far as tracking, did they just post it 2 days ago? It's not uncommon to generate a tracking number but not deliver it to the courier for a couple days, and it subsequently taking another couple days before it makes movement in the courier's system, even in the best of times, which are not right now. Give it a few days, use something like 17track.net or parcelsapp to cover your bases on various courier systems and see what happens. If you don't see movement within a week or gotten no satisfactory response from the seller, contact Paypal and open a case.