I get it, people move on, changing needs, etc. I would be super pi$$ed that she had the nerve to contact other daycare families, regardless if they left or not. I think you handled it very well but I would be actively looking to replace them now. This family is not anyone that is going to stick around and will try to get other families to leave with them. They have shown this to be true. I also would not ever use them for a reference. Ever. Sorry that happened to you.