I am very sad to know this

I got my green card more than two years. I don't know I-824 before.
My exhu*****and divorced me and he gave my daughter's custody to me.Now he said he applied my daughter's green card one year ago. But I have to give my daughter's custody to him. ( He sais he is too busy so my daughter still will live with my). He lied all the time so I don't know what he said is true or not.
I want know how I can find out my daughte's green card status.
When my ex abondend us. I didn't have money and job. And my ex controled my visa also,. Now I got green card and for god's sake, I find a job. So I want bring my daughter here.
Please give me some idea.