My mother is truly awful and I barely have any contact. By barely, I mean she tried to contact me through my enabling father, and I ignore her.
The last time my mother mentioned the wasted investment in me was in 2016 after a near death medical emergency. She has never mentioned the money since she said it about 15 years ago. At the time I agreed to it, and about 10 years ago I also, without being asked, put to her in writing that I will pay her back as she was sending me abuse over email and I wanted to tell her once my debt is paid there will be no obligation for contact.
I have this hanging over my head now, because I promised, but also because I am about to have a second child and when she tried to come back into my life I want to be able to tell her that I have fulfilled all my obligations that she may think I have, and she can go away.
In terms of the return on investment, she wanted me to turn out to be a particular kind of person and I haven't. Some of it is superficial eg having nice hair and skin, some about life choices eg being married to a rich husband and me be a housewife.
The reality is - and I don't mean to sound boastful - I have a high powered job making lots of money through my own work rather than my husband, i have bought my house outright using my own hard earned money but it "only" has 5 bedrooms and not 8 or 9, I have health issues which means I don't have long, lush hair like Kate Middleton but I still look nice. And because I don't have these things and many other qualities, I'm a failed investment.
I must keep her away from my children and the only "claim" I can think of that she has is that I owe her for raising me, so I want to make sure the promise is paid off so she no longer has that claim.