document every thing. I mean everything. Then you would have to hire a lawyer and sue for custody. I have 3 sons and 2 of them have full custody of their kids. You have to build a case that shows what you know to be the fact. Courts only listen to facts proved by evidence. It takes patience
Document, Document, Document !! I have custody of my two son from my ex-wife for 8 years now (they were 3 & 7 at the time) It does take patience and work on your part. Make sure you keep a diary of everything ( no matter how small) that happens, like calls from your child, and her mother , what time, date and what was said, also try to get friends or teachers to help if you can. A good child custody attorney, and no matter how upset you get always keep your cool ( she may be recording you or keeping a diary on you) It wasn't easy for me and took some time, but no matter how frustrated you get keep in mind why you are doing this, for the Love your child. Good Luck!