This kind of behavior points to a lack of control on her part. She's going to continue to flake out if she's off meds. I've been there, remember? I don't think talking to her is going to get anywhere until that happens, unfortunately.
But if it's not something you are willing to bring up, I wish you the best of luck figuring this out. At the very least I believe Melissa will have a good life with you as her father.