Fuzzy Math at Amazon Book Sales

My Dad wrote a book - UNIQUELY HUMAN that was published back in 2012. It ended up at Amazon books and they have been selling it for the last 4-5 years. It was #1 in sales at Powell Book Stores in Portland  for about 4 weeks . In this span of time he has never received a nickel from Amazon. When you call Amazon you get passed around so many times it feels like a Merry Go Round.

I am curious to find out if there are any other authors out there like my Dad that have been miss-treated by Amazon? I am wondering if anyone has spoken to the AG in Washington? I would appreciate any insight you can share. I am trying to help my father I believe he has the right to know the truth.