I am not her parent!!!

I am the single mom of 2 kids, I work full time and none the less, when my kids want to do an after school program or sport, I figure out if and how I can make it happen before the sign up. I find out cost, practice schedule and try to arrange with another parent a way for me to pick up part time and them to. Then I tell my children yes, we can make this work, go for it. Well I have spent this whole season with a child who isn’t mine becuase her parents let her sign up but they don’t have a car so can’t get her home, they can’t get her to games or home from them, they forget to pack her a lunch (I now just pack extra). I just don’t get it, why let your child do something you can’t and don’t support? UGHHHHHHH