I can understand how the readers of the book may be disappointed after watching this series. Reading an exciting book and then seeing it being destroyed in the movies.
But I actually enjoyed it. I have to admit I didn't read the book and I can't make a parallel between it and the series but maybe I don't have to. This was another perspective of the Ice Cream Girls story and it can be appreciated even if you haven't read the book.
I really felt for Poppy. Her struggle, her loss, no one believing her side of the story. Seventeen years lost in jail for a crime she didn't commit. It seemed really sad for me.
I did't expect the ending and as I have understood it is different from the book, but I have really enjoyed it.
My advice is to stop comparing movies with the books because you will be disappointed every time. Try to appreciate the series for what it is.