This is another good example of why you get paid in advance. If they short you two days, then you ask them what days they are not coming. If all the families do it , I would close on the Friday and Monday with pay as per your contract and then warn them all that you will be closed the following Thursday and Friday as well unless you receive payment. I did have one family when I first started try to drop their children off on the Monday, I was away, my neighbor watched laughing as the dad tried my door three times .... That taught them to read the bulletins.