Are receipts required for unreimursed expenses?

I have a divorce decree in NY and my ex is an attorney and wrote the agreement (now court approved). My question pertains to unreimbursed expenses and receipts. Each quarter she gives me a hand written list of expenses and the amount I need to reimburse her for. She has never given me any backup to show these expenses are accurate or real. I have recently requested the receipts from her due to multiple errors and she is telling me receipts are not required because it they are not in our divorce decree. Am I required to pay my share for unreimbursed expenses without backup or should I continue to hold out for the receipts? Thank you, D