Babysitter stood up, what would you do?

I had babysat for a week, with the promise of being paid at the end of the week. I had done this with others and had no problems being paid, but this particular couple would have me come to their house and watch their 2 children all stinking day and then stay out until 11 at night and say "sorry" when they got back....(was supposed to be until 5) The last day they brought me home at night and said they'd have the check for me the following day. They never answered their phones, their door when I went to their house etc. should I have sued? (My dad was so upset about this unjustice he paid me the amount that they promised,, but why should they get away with that?!