One of my parents (parent 'B') was consistently unreliable in terms of emotional support and educational development when I was growing up; they never wanted to spend time with me and I often felt like I was a burden to them rather than a son. During college when my parents divorced 'B' put my other parent, (parent 'A') whom was always there for me and whom I cared deeply about, into a major bind and filed for bankruptcy, which placed 'A' with all of our family's debts. Furthermore, because 'B' filed for bankruptcy, and 'A' was buried in debt, I then had no way have a co-signer for loans, and I thus suffered many difficulties in college: at times I became malnutritioned, and I was intermittently homeless. Now I have just graduated with dual degrees in Mathematics and Physics, and I plan to pursue a PhD at UCLA (which is very well-funded by fellowships/scholarships). Now 'B' wants to reconnect and seems like they actually want to be a parent, but I don't have any interest in connecting with them. How should I handle their approaches? For instance, 'B' will call me weekly, but I haven't answered for the past 3 weeks and either just cancel their call or let it go to voicemail, is there something more productive I can do?
One obvious idea is to tell 'B' how I feel, but I don't even feel comfortable sharing any feelings with 'B' because of how they have neglected me in the past.