I've had a similar experience, though not in a work context. I went to see my mother, and to help her out with a few things. She spoke more loudly than she thought she did, because of deafness. She was speaking on the phone, and I overheard it all. Very cruel and hurtful things about my appearance, dress sense, and similar, and untrue things about my husband. I told her straight out, and immediately, that I'd heard everything she said. It wasn't a shock, because she'd said things like this all my life (she was in her 80s at this time), but it was very upsetting. I confronted her with it so it wouldn't eat me up. She burst into tears and asked for forgiveness. She didn't get it, at least at the time, but we didn't discuss it further. Confronting her helped me to deal with it. I think, whatever age you are, and whatever the situation, if you say something it can always be reported back, and if you write something it can always be seen - and sometimes the person wants it to be. But whoever says or writes something is responsible for it. It's no one else's problem. This is not your problem, and you can move on with a clear conscience. You have tried to help, and it's not appreciated, and your daughter doesn't like or respect you. You don't have to cut off contact, but you know where you stand, and you owe her nothing.