what should i do first before filling out child support papers that r being sent against me eventhough both parents have verbal agreement on 50/50

You need legal advice, not merely this response.  If you can hire a family law lawyer, do that- if not, see the Family Court Facilitator at your local court house, who can best advise you as to how to go further.  Verbal agreements are worth the paper they are not written on- you can't rely on them.