adoption

My daughter was unable to raise her unplanned child, would not allow me to raise or adopt, nor any member of family, wanted to go to a home for unwed Mothers and allow a stranger to adopt. After much pleading, she did, however, allow a childless couple I knew to adopt since she is not from the same town as them, and I could be a part of the child's life.....the couple gave me their word that they would allow me interaction, if nothing more than to keep me informed of how she was doing, allowing me to send gifts, they agreed to send pictures.
We were most cooperative in the adoption process....The father was diagnosed with cancer two months later, died two months after that. Now, I am unable to get the Mother to respond to me when I write, send money for photos (no, she doesn't cash check either). I feel she is not honoring our agreement, but feel helpless to do anything about it. This is my grandaughter, she is now 14 months old, I don't even know if she smiles....Please advise~