Am I making a big deal out of this? Maybe i'm being too sensitive...

So I had siblings in my care for 3 years (the older one 3 the little one 2)
The Mother says the older girl will be starting after school daycare in her school NEXT WEEK
The younger boy is going to stay here as he isn't in school yet.
So then the dad later comes to me and says....."I want a refund for January for the older girl since I already paid but she won't be here as of next week."

K...So it says in my contract thirty days notice paid AT LEAST for termination

And now they demand a refund after giving me a weeks notice???!!!
And at Christmas time to boot?
And I charge the same as the school daycare does!!!!

I raised their kids for them! Talk about gratitude! I am in shock and I am also flabbergasted and I am also confused as to why they bothered taking her out at all since her brother is still going to be here.
And also I feel totally treated like a piece of garbage.
HELLLOOOOO I have a family to take care of! Bills and all. UGH!!

Am I being sensitive? How would you feel? What would you do?

It baffles me they demand a refund and their son is staying here and it says thirty days at lease paid notice.