I would assume that she is not coming back....I can see how they might be uncomfortable bringing their child back when you have given them notice that it is not working. Also if she was Sick for long what is the point in brining her back..... How many days are left before the end date you gave them? We don't always get the reactions we want from clients , you' ll just have to accept it, let it go and move on....good luck witha fresh start with a new client.