I used to know someone who had borderline personality disorder who did the same to me. She also did that to a lot of other people. I don’t think everyone who has “borderline” pd does this. I think you are responding to it in a “mature” and sensible way. I also care about friends and even some ex friends (so long as they were not so unwell that they demonised me....

ETA hopefully your friend was just having a bad day and will stop being mad at you and will unblock you.