Child support arrears

Father ordered to pay child support for years. Daughter turned 18. Father $14000 in back child support. Received statements which states he is this amount behind. Then states arrears amount of $30. Received payment which was $36. If this is correct it will take 40 years to pay off. Is he suppose to pay the monthly payment as though the child was still a minor? Father works under the table. Does not pay taxes. Though newspaper has him stating how he has a business.