I have found myself in a situation where a Type Nine ISFP I know (not a close friend, but a good acquaintance with whom I have a meaningful connection) has been flaky and hurt my feelings very badly. You can read about my experiences with her in these two posts:
This one happened many years ago:
This one, last October:
I am planning to call her in a couple of months about something practical I need to ask her, but I would also like to talk to her about what happened last fall. How should I proceed?