Abandonment Issues in reunited bio siblings?

*WARNING* *LONG POST* I found out I have a half-sister 13 years my junior in spring 2020 (the beginning of the COVID pandemonium). I contacted her via Facebook Messenger and we later would do periodic video chats, but primarily we communicated via Messenger. Initially, everything was great. We clicked right away, and we messaged each other multiple times per day. Her and I both grew up as the only child in our adoptive households, and we both became really involved in our new relationship (to the detriment of our in-person family relationships). She was in lockdown and had unlimited time to message back and forth, and I work a job that allowed me to be on my phone throughout the day. Every day, the person we had contact with first thing in the morning and last thing every night was each other. In retrospect, I realize that this was not a healthy, sustainable way of communication. The issues began very shortly after our initial contact. If I said something that would upset her, no matter how benign, she would go into "radio silence", refusing to acknowledge my messages for hours, sometimes days. This would drive me crazy, eventually I would have a sobbing meltdown. I would keep attempting to initiate contact, only getting a response after multiple attempts. The responses I would receive would be cold and sometimes mean-spirited. This same push-pull dynamic kept on happening over and over until June of 2021, when I finally decided I had enough. I called her out on her BS, and she responded in her usual fashion, accusing me of contacting her too much. I just got fed up and blocked her on Facebook. Throughout this entire time, I have had contact with her adoptive father. He and I share common interests, and we share light-hearted messages and jokes from time to time. Recently, I contacted him to see if he thought it would be worth it to reach back out to my half-sister. He asked her, and later that day, she e-mailed me. I was optimistic that we could maybe get to some normal relationship, but in our few interactions, her messages are very terse, and when I broach the subject of a phone call or video chat, she claims to be too busy for a phone call. I held back on responding, hoping to come up with an adequate response. Then, last Friday, her dad called me. In our hour-long conversation, he revealed something to me that I never knew. Ever since an early age, she has suffered from abandonment issues. (I forgot to mention that she was adopted at the age of 2 via a family friend, and had contact with our birth mother until her death in 1998. I was adopted via Lutheran Family Services and my records were sealed) He has encouraged her to seek counseling, which she refuses to do. I have just begun researching abandonment issues and their affects on adult relationships. What I've read so far reads like a script written about our relationship. The question I have for this forum is: Have any of you dealt with this issue and if so, what are some effective tactics to deal with the withdrawal/mind games/ etc.???

This is a pretty tricky situation. I recently did 23 and Me and found my birth mother (September 2021). Her and I are VERY similar and we hit it off right away. In my case, I'm the one with the severe confidence/abandonment issues. The issues don't seem to really stem from anything, but the reactions you get from your half-sibling are similar to what I show when I'm feeling this way (although my episodes pass within hours). My situation is different for multiple reasons. First, my birth mother has all sorts of "mom" instincts with me, so she's willing to support through these issues. I'm also an active, open communicator, so we discuss these issues. Finally, I'm actively working on these issues. The point isn't to give you my life story, but to highlight that the effort is not yours to make to try to fix these issues. However, you could attempt to prompt discussion of her issues, and try to find ways to improve them, at least as they relate to your relationship with her. If you decide to do this, you should be prepared to potentially be a support structure for her with regard to these issues (up to you to decide how much energy/bandwidth you have for that). If you can get her confiding in you about how she is feeling without her feeling that she will be judged or shunned, you'll really have achieved something. If she can trust you to "know" her feelings and thought processes, perhaps she can begin to trust that you won't embody the fears that cause these feelings. I know this isn't really "advice" per se, but I do believe the only way to break through this is if you can get her to talk about it, otherwise her mind is going to create whatever narrative it creates by default, and with these types of issues, that narrative is always going to be that you hate her or have abandoned her, no matter what you do. Good luck. I hope this has a happy ending for you. I know what it's like to find people who are similar to you as an adoptee, and it's life changing.