Just think of it this way: They don't know what they're missing!
I had a lady cancel an interview with me, and left a message stating "I have found a better and cheaper daycare than you". I was pissed at first, but glad I didn't waste my time with her. Apparently money is more important than your own flesh and blood. Good for you!
OUCH! That's just mean and oh so unnecessary. How would she even know this other dc is better when she didn't even come to the interview?