Either prove that he faked his hacking or stfu.
What the rule says is irrelevant, anybody with half a brain knows that the rule in its current context, relating to hackings, means that the PM is to verify that you are currently talking to the correct person and not a hacker. Its basically supposed to be a no-brainer method to prevent scams whereas the hacker only gets the person's skype, and not their sythe account as well. That is, until idiots start running amuk around the market trading when they don't have a high enough IQ to wipe their own ass.
That being said, much like the real life justice system, no rule or law explains every aspect of it, there will always be loopholes and ways for people to interpret it differently, even if it should be common sense.
tl;dr dont be a fucking idiot and use a pm from a month ago as proof that somebody isn't hacked.
Also don't argue that "a lot can happen in an hour" because we all know that you're just being hard to get along with because you lost some money by being dumb. If you had a PM from Lean an hour prior in the same conversation and he claimed to get hacked in that time frame, there is no doubt in my mind that every single person on the staff team would rule in your favor.
Oh, and this just in, there is proof that Neanderthals are still wandering the earth, and have learned to use computers.