family feud over my daughter

im an african who left my daughter in 2002 with my sister and her husband ,they moved to  to a counrty where my brother stays but my brother insisted in taking my daughter to care for him as he is the first born in my family.i di not see anything wrong at the time untill he send my daughter to stay with his inlaws some 400 miles away from him,i asked him n told him i was not happy he would rather send my daughter to my sister if he no longer want to look after him but he threatened me with sending my son to her father whom i divorced some 11 yrs ago.i was granted status in this country recently thats y i couldnt take my daughter and i asked him for her passport details  so that i can process papers for her to come hrer but he denied to give me saying i mustnt contact him whatsoever if i want anything from him i was to go through a relative.he send me 2 emails nasty ones claiming money with interest for looking after my daughter and wanting the money as soon as possble so that the bill and interest wont go up.he does not want to give my son to my sister he said she has no right to look after her if he cant look after her she has to go back to her fathers house.he has send me n email he has send it to the home office wanting my status to stay be taken .please help