So I contacted her and asked her if she would like me to apply for the insurance on my computer. Her ex husband stole her computer. She agreed. I’m very skilled at helping folks with the state insurance process. This is one of my duties at work. One of the questions was asking for her SS#. She flat out refused to give it to me.
Sigh. The intense challenges that come with BPD never cease to stop us in our tracks, right? My defining moment with my uBPD mom was different, but just as crazy, so when I read this in your post, I wasn't surprised.

You were reaching out to your sister to be helpful at a time when she was in a critical mess and couldn't help herself, and then she turns that around into an epic conflict and blames you. I so get it. You are not alone. The good news is that it can get better. You have found a community here that will understand and support you, and the resources on this site are amazing. They can help us learn to manage and navigate a high conflict relationship, including our responses to the person that causes us distress.
When I hear that she accepted your help, but then refused to give you the SS#, I can't help but think there was some other underlying reason for her refusal, that you don't know about, and which had nothing to do with you. For example, did she lose the card/# and/or is she feeling intense shame for not being able to give you the # (because it makes her look bad)? Or, is she afraid you would use the # to look into some of her personal information (which she feels shame about)? Or, perhaps she had some terrible experience in the past with someone who asked for her SS#, and so your asking for it triggered her nasty response? None of these are excuses for her horrible behavior towards you, but it could be helpful to think of the blow up in one of these contexts, if it helps you to see it probably wasn't personal. It took me a LONG time to come to realize that my mom's behavior towards me might not always be personal, because it sure felt personal. But if it had been one of your employee colleagues helping her with filling out the paperwork instead of you, it's also possible she might not have blown up at them the way she did at you, because she actually feels safe blowing up at you (because she knows you care about her). It's the nature of the disease. The relationship conflict is usually with the person the pwBPD feels safest around, and thus affects the intimate relationships (usually romantic or family or BFF) the most. It's brutal, and can lead to the person going either no contact or low contact. Ironically, this is what BPD's are most afraid of, is "abandonment". It's like a self-fulfilling prophecy, and it's horrible, but ultimately we are not doormats for someone else to abuse, and we must take care of our own mental health.
I was able to advance to the next screen without it. I told her this. She then screamed at me saying - “if you don’t stop this process, I’m reporting you to the state for fraud”, I said- “WHAT?” She was trying to compromise my professional license that I have worked so hard for. I’ve been in the field for 25 years. My best friend told me that she would have been done that day with anyone who compromised her ability to earn a living.
Absolutely. I'm hoping you stopped helping her at this point...and aborted the computer application?
Her behavior doesn't make sense. It's completely irrational. If she's BPD, she doesn't think rationally. She acts on emotions rather than on rational thinking. She likely doesn't have executive functioning in her brain (the rest of us do) because it's not wired up for it. Something about your request for her SS# triggered her emotions. Not your fault. After that, her brain stopped working, and chaos always follows when the emotions of a pwBPD go off the rails. Sadly, when she yelled at you that she would report you for fraud, she could be projecting what someone else has said to her in the past. That way, she gets to dump her horrible feelings on someone else - in this case you. Again, not personal, just the disease.
Maybe I was not done with her yet. It’s been difficult as I love my sister and feel sorry for her with all of her health issues. I came to the realization that she is truly mentally ill and she doesn’t want help.
Yes. This is often the first step towards our own healing from all the hurt that comes from having a relationship with a pwBPD. Acceptance. At least this is how it was for me. Once we accept our loved one's mental illness, we can move forward with our own healing if we choose.
I realized that my self worth, character, reputation, and integrity are worth more to me than keeping her in my life. She is jealous and envious and she’s in a lot of pain, but chooses to not deal with it.
Yes yes yes. Your priority has to be your own well-being. Perhaps this has been your defining moment or epiphany, where you can fully appreciate that you cannot continue to fix or rescue your sister unconditionally forever. It is beyond your control, and so maybe it's time to let go of thinking that you have to?
Focus on your own well being for now. Take a break from her, and give yourself some time to heal yourself, before you come up with a plan (eg no contact, or low contact with boundaries etc). There are lots of strategies on this site which can help you.
Again, welcome to the forum.