Child custody and child support are two completely different aspects of your agreement with the other parent. On one hand, you have a plan that dictates when you see your child and when they see the other parent. On the other hand, you expect payments to be made on schedule in accordance with the court order.
The one thing you cannot and should not do is withhold custody if you don't get a child support payment as you expected. Doing this is unfair to your child, a violation of the other parent's right to see the child and against the law.
Don't make the mistake of withholding visitation over child support disputes or nonpayment by the other parent
Consider this. Each parent has a right to visitation. Each parent also has a responsibility to pay for a child's financial needs. It is also your child's right to receive support and to see both parents when doing so is safe and appropriate.
It is best not to withhold custody if the other parent doesn't pay support because doing so hurts a judge's opinion of you. That's something that no one wants. Additionally, withholding visitation could be used against you and could even be an act used by the other parent to seek more custody time.
It's smart to think about custody and child support separately because they are separate. Your child's right to see the other parent doesn't change if that parent doesn't pay support unless a court agrees that it's not in their best interests to see the other parent moving forward.