Hi Juliasnani,
I want to join
Feeling Better in welcoming you to the forum. Having a BPD daughter, 21, myself, I truly understand some of the behaviours you speak of. She too has been very impulsive with money and I certainly have seen more than my share of sullen behaviour as well!
It is excellent that you are informing yourself by reading "Stop Walking on Eggshells". The resources on the right hand side of this page

are also full of excellent tools and lessons that can help you better communicate with your granddaughter as well as think about whether there are things about your approach that you could change.
You are feeling that you need to disengage from your granddaughter for the time being and wait for her to reach out to you. Is this the first time you have tried this approach? When was the last time you had contact with your GD? How is her mother, your daughter, coping?
We hope to hear more from you,
Juliasnani. There are many others here who understand where you are coming from... .having a loved one with BPD can be an exercise in frustration and patience to be sure... .
MomMae