I'm sorry you are having issues purchasing it. I'm not sure what the problem is with Paypal. I do not have any control over the payment processing on Itch or any other platforms. I really can't just update chapter 8 because it was sold clearly as a separate chapter. I had been asked to offer different ways for folks to get the game. It was only after this chapter that I changed to a model that included all future chapters too, for a little bit more.
Just for reference in the past month I have sold a grand total of 2 copies of the game on itch and those numbers are better than on Steam. The de-listing has really hit hard for us adult indie devs and honestly those sales numbers are not enough to sustain my ability to continue to put in 10 - 15hours a day, every day to develop it. I'll finish Best Friends but I will seriously have to look at if it will be financially possible to produce my next project. There will be a lot of devs that will come to the conclusion that it's not.
All I can suggest is that the game is available on other platforms, Steam and Patreon. A quick search will find that, the Steam link is on the store page I believe.