Alienation of my children from me to gain custody

[frankt]

I have been through a family evaluation to detemine custody for four years now.  The evaluator sided with me a year ago and then my ex had my eldest daughter who was 19 go in and talk the evaluator into changing to ex's favor.  Went into mediation and decided on split custody where I have my younger son and she has younger daughter who is 10.  Now ex wants to renig on the mediation and go after custody of my son after 8 months of living the mediated agreement which she refuses to sign.  The evaluator wants to amend the evaluation.  My 10 year old daughter has been alienated from me as well as my 21 year old.  Now she is working on my son.  I had the younger children in protective custody for two years as her new husband abused him three years ago.  Ex supposedly recovered from prescription drug abuse but I am doubtful.  She has been diagnoseed bipolar and histrionic.  She just declared chapter 13 and house has been in foreclosure. I have a totally clean record.  I feel like since I am a man that everthing is totally biased against me. She is really working to alienate each of our children from me systematically.   Help!