To summarise, you came here looking for advice.
Everyone advised you to ask for the CPU to be returned to you, such that you could check a) whether the buyer sends you back the right CPU, and b) if the correct CPU is sent back, whether it now has bent pins. You were also advised to be cordial with the buyer in the meantime so they didn't maliciously bend pins on the CPU before sending it back.
You appear to have ignored this advice, instead sending the buyer a message questioning the truth of their previous statements (i.e. implicitly accusing them of lying), and they have understandably not taken too kindly to that. Imagine if you bought a CPU from an online retailer, you sent them a message stating the pins were bent on arrival, and they just responded with words to the effect of: "Nah mate, that's impossible. You're talking nonsense."
All the while, the buyer seems to have been more than reasonable, even offering to send you photos of the bent pins. Why would they even offer to send photos if they were scamming you? Why would they call your bluff like that when it's completely unnecessary?
Keep asking for the photos. As far as I can tell from the communications you've posted so far, you've only asked once.