Wolf, She isn't letting you talk to your children at all? Going dark is good, but that doesn't mean not talk with your children also. Don't feel bad about trying to talk with them. In the last call, did you get to talk with them? Or did it just turn into a conversation with your wife?
I would get proactive in defending yourself and your rights as a father? With you not seeing them or talking with them regularly, her lawyer could twist everything to look like you abandoned them. Be careful....it sounds more like your wife is taking aggressively hostile advice from her parents than anything else.