If you have not paid child support or have not been receiving the child support you are supposed to get from the other parent, there is a way of collecting that money later on. It is known as back-paying support, and it's how children can eventually obtain compensation for child support they were supposed to get during their years growing up.
One parent typically owes support during a divorce. That parent is expected to meet the obligation monthly or in whatever way the court agrees to. State guidelines generally state how the obligator has to pay the recipient over time. If the correct payments are not made, then the person who was supposed to be paying is considered in arrears.
Just like falling behind on payments of other kinds, missed payments become a debt. They aren't forgiven. If a parent misses several payments, the length of time they need to pay child support or the amounts they owe may increase.
Anyone who has not paid support as ordered will need to make back payments. On top of the original bill, there will also be interest charges, fees and other penalties. Typically, the states only handle back-child support once a person is at least two years behind on payments. At that point, the parents are informed that they will need to pay the support in full, even if the child has now reached the age of majority.
If your child's other parent has not made timely payments or if you have missed payments, they don't just go away. If support is in arrears, it is an obligation to obtain those funds for your child.