M.B.
I would say to forget it. Just hearing what happened already would tell me that they really don't listen to their employees. For a minimum wage job...it wouldn't be worth it to me. What happens down the road when they need people to work a little over time (Christmas comes to mind) and you tell them you can't because you have to be home for the children? I would look for something a little more family friendly...and emphasize the importance of your family to them. There are quite a few Walmart type places out there that are (or will be) looking to hire because they want people to be established before the holidays.
I personnally would keep looking just for the simple fact that I would have a chip on my shoulder about this (my husband says I can hold the best grudges...LOL) and wouldn't think to kindly of the organization as a whole. Why would I want to work someplace that has so little respect for my "full-time job", my love, and my life (ie my family)?