Yes I have to agree with you. You are too nice
. I would give her a notice/invoice of what is owed to you (and deduct the $100 if it's what you feel you should do) and then have a sit-down with her and talk to her about the money issue, talk about how she was supposed to have it paid by the summer and it still hasn't been paid. Negotiate a payment plan for this to get paid off. Start by you telling her you want her to pay an extra $X amount of dollars a week and see what she says. If she doesn't want to cooperate with you tell her that you have received multiple calls for a spot that her child has and that if you don't worl out a solution to have the balance paid that you will be forced to replace her child. Reassure her that you don't want to do that (if you really don't want to terminate her) and would rather work with her instead but you need a commitement from her to pay what is owed to you for services that you have given them. Hand her the written notice/invoice which says exactly what you have covered with her verbally and then take out a pad of paper and a pen and draw up a payment plan contract and have her sign it. Don't give her more than a day to think about it as it will only postpone you getting your money.