Ordered from eBay, get item from Amazon. eBay shows different tracking number.

[ca.men9]

I recently purchased an item(Lego Skyline London) from eBay. The seller provided a UPS number A. But then later I received the item from Amazon(nobody knows I want to buy this, so 0 chance somebody bought me as a gift). I know there is a concept called dropshipping. But tracking number provided by seller on eBay is different from the one on Amazon package. 

Amazon package was delivered on 20th April. The UPS number from eBay showed it was delivered on 28th April, but I didn't receive anything, so it just seems like the UPS tracking number is a dummy one(but it does have all the tracking details all the way to my county).

And the seller is not a registered user with eBay anymore. eBay seller page shows he is a user since April 2021, just several days before my order.

I don't want to take any advantage from the seller, I paid the money, I got the item, that's all what I want. Just curious how things(especially the tracking) work inside all of these.