A contractor who receives a progress payment or a final payment shall pay a subcontractor or supplier an undisputed amount to which the subcontractor or supplier is entitled within 10 calendar days of receiving the payment. If a contractor withholds payment from a subcontractor or supplier within the time period in which the payment normally would be made, the contractor shall: Notify the subcontractor or supplier in writing and state the reason why payment is being withheld; Provide a copy of the notice to the prime contractor or supplier and, if different, to the person or firm that made the progress payment or final payment to the contractor; and Provide a copy of the notice to the procurement officer. Written Notice of Nonpayment. If a subcontractor or supplier does not receive a payment within the required time period, the subcontractor or supplier shall give written notice of the nonpayment to the procurement officer. The notice shall: Indicate the: Name of the contractor and, if different, of the prime contractor; Project under which the dispute exists; and Amount in dispute; Provide an itemized description on which the amount is based; and If known, provide an explanation for any dispute concerning the payment not received.