I read all 10 pages of the original thread, but I'm not reading all 47 of this one.
Just wanted to say that no matter how much you 'know' a customer is lying, they are always right. I work for a restaurant, and we get liars calling every day saying we messed up their order when multiple employees remember the order leaving correctly. You never call them a liar, you never argue, you offer to fix your 'mistake' so that the customer's lie doesn't turn into bad PR.
A1 company fail, and A1 poster fail.