Ebay seller sent item without being paid?

So, I was looking to buy an iPhone on eBay and I found one that to me was too good to be true so I bought it but I asked the seller if there was anything wrong such as cracks or bad ESN and then a few seconds later I receive a message saying that the seller canceled his/her sale. The day after I bought an iPhone but from a different seller and I was like alright, I finally bought one. A day after I receive a message from that first user telling me that if I was still interested in buying it, I could send funds and they would ship it but I never responded nor sent any funds. Well a week later (today), I received an eBay message saying that the seller sent the item and included a tracking number but the thing is, I have no plans to pay for it because I already bought another one. What should I do, should I just tell the mailman that I didn't order that and send it back?

Added (1). I'm going to call if this user doesn't respond back by tomorrow!

Refuse delivery on the phone. Call eBay customer service (takes a while to get through sometimes, but they're helpful) and ask them how to handle the situation.

I'm not telling you to return it our whatever but i would because he might report you and if so that would be bad but I'm not too much of a Ebay user so I'm not sure what they can do.

Return to sender and send No money. There's a Scam concerning iPhones going on from some Thieving B---d in Africa so watch what You do.