one word: WOW!
Goq-im so sorry you are going thru this. It’s so hard when there is a dispute or an ignoring situation going on. Maybe you should talk to your sibling of whom this daughter belongs to and see what is going on with her. It seems maybe you need to be direct with her and just let it out! Write her this letter for real and let her see what she is doing to you. Sometimes a letter hits harder than an actual conversation! i wish you much hatzlacha!