Apple

So i found an i phone 13 pro max 256 in a second hand selling website a talked with the owner to buy it he said that he got it as a replacement from the insurance for his old i phone being damaged and not being able to repair it they gave him a replacement that he didnt even open before he juste got it out of its case. What do i look for in this situation to not get scammed I heard people say that once the guy gets my money he will report his phone stolen and get a new phone how to protect myself in this situation? Should i make a selling contract? Thanks Ps:the price is 800$