Tax and child support question. Please answer.?

My question is this, I have a 8 year old son he lives with his father, I pay child support for him, I also have a 19 month old son, and a baby on the way. Last year on my taxes I claimed my 19 month old son, and I was issued $1000.00 specifically for my young son, I owed back child support, so my whole tax return was withheld to pay the past due child support. I am just wondering if the money that was meant for my baby was supposed to go toward my other child