If you’ve received a contempt notice for failure to pay a child support order, be aware that the judge can put you in jail. The constitution guarantees you the right to an attorney when your liberty is at stake, but your county may or may not provide this to you; assume that you won’t be able to speak to an attorney.
Your ex can not keep you from seeing your child if you are behind in child support. Courts are organized into separate family law categories: support, custody, and divorce. Child custody and child support are separate. Good or bad behavior in one does not affect the other. Your ex can’t withhold your custody time if you’re behind in your child support no matter how much you owe or how far behind you’ve fallen.