I just spent over an hour on help chat.
3 different 'people', but I don't think any of them were real.
They ignored the fact that a books significantly outselling a previous book has a significantly worse rank.
And all they did was quote help system text at me to justify it.
Apparently I am escalated to a supervisors supervisor now, but 24-48 hours to get an email response.
As far as I'm concerned, the Amazon rank system is BROKEN.It could be the book got broken by the same problem with Pre-orders, but who or whatever I was just chatting with won't even concede that there is a problem.
Nor would they even submit it for further investigation.
Whatever bot system they're using now for chat assistance is broken.
Email assistance was not even an option. Maybe I'll get something in a couple of days, maybe not, but my guess is, I get the same canned responses they parroted at me one by one in the email.

They couldn't answer this basic question.
How does a book doing $16 in one day in one store, have a 21k rank, when a book doing $125 in the same day in the same store has a rank of 104k?
They had no answer to that other than 'hidden algorithm'. And the ranks are confirmed correct.
In all respects, the just released book is doing just as well as the previous ones, and should have got down to a rank of better than 2500. Instead, it's never dropped below 103k.
BROKEN!