You can't have everything, where would you put it?

[awest1217]

Or if nothing else, make a plan of action for when the girls are with you. Sit down and talk with them and give them consequences for when they are with you for not turning in homework.

My biggest issue is you constantly saying "it wasn't my night". The girls are always yours and they need to know that you are going to discipline them for not doing stuff just like their mom will or should. So come up with some consequences for any missing homework no matter when it was missed (unless it is turned in by the time you have them, then there is no need for a consequence because they completed the task).

I did this with my little sister. She was in high school still when I moved out. If I found out she was failing a class or was missing assignments I disciplined her because my parents wouldn't. I was her ride many places so I told her I would take her to church and straight home. I didn't care how much she complained that was how it was until she got her grades up. To this day, she knows that if I find out she is doing something wrong I will get after her and she tells me thank you because she knows I am consistent and I care about her.