perhaps you could apply for joint custody-you and the father if you feel that your daughter cannot care for your grand daughter. that way you would still get to see her and so would her father. perhaps your daughter needs to go to rehab or some similar program-if the courts see that she is trying to recover and get help they will be a lot more forgiving with regards to custody i would imagine.

You need to seek professional legal advice to try and gain custody. I feel there really is no other way. Does the child's father live near you? Would he make a good father to your granddaughter? I understand that you would rather have your granddaughter with you but the courts will look to see who is the most suitable individual to look after her. Begin making a case for yourself by writing a diary and showing what you do for your granddaughter, times and places of trips out etc. Photographic evidence to back it up will help. Also try to detail any episodes when she has seen or been contacted by her father this will help to ascertain suitability. I wish you the very best of luck, keep trying to contact your daughter.