You would probably do better to use a collections service rather than small claims court due to the costs involved - although they would be claimable as a daycare expense but collections is a lot less work for you since once you pass the amount over the rest is up to them.

I agree that it is time to make up a chart of the amount owed and give it to the parent with a deadline to settle the account or risk losing services. Following that the money is due on Monday at drop off in cash - I wouldn't be taking a cheque from someone like this due to risk of bouncing. If she only brings part of the money then the girls stay according to how far the money goes be it 2 days, 3 days whatever. It is a no pay no stay policy for sure with these people because they are not valuing your service as a necessity.