They just recently took my tax refund from me due to i owe back child support but i pay monthly and havent missed a payment. wondering why they did that?

You need to contact the agency that seized you refund. In most states, this is called child support enforcement or something similar. You need to review your account and confirm that there are no mistakes in their records.
If they've gone far enough to seize a tax refund, it is likely that your driver's license may also be suspended, and/or your wages could be garnished.