(a)(1) Carriers shall establish procedures for identifying and properly applying all unidentified payments. If a carrier does not have sufficient information with which properly to apply such a payment, the carrier shall notify the payor of the unidentified payment within 60 days of receipt of the payment and request information which will enable it to identify the payment. If the carrier does not receive the information requested within 90 days from the date of the notice, the carrier may treat the unidentified payment as a payment in fact of freight charges owing to it. Following the 90-day period, the regular claims procedure under this part shall be applicable.

(2) Notice shall be in writing and clearly indicate that it is a final notice and not a bill. Notice shall include: The check number, amount, and date; the payor's name; and any additional basic information the carrier is able to provide. The final notice also must inform payor that: (i) Applicable regulations allow the carrier to conditionally retain the payment as revenue in the absence of a timely response by the payor; and (ii) following the 90-day period the regular claims procedure shall be applicable.

(3) Upon a carrier's receipt of information from the payor, the carrier shall, within 14 days: (i) Make a complete refund of such funds to the payor; or (ii) notify the payor that the information supplied is not sufficient to identify the unapplied payment and request additional information; or (iii) notify the payor of the carrier's determination that such payment was applicable to particular freight charges lawfully due the carrier. Where no refund is made by the carrier, the carrier shall advise the payor of its right to file a formal claim for refund with the carrier in accordance with the regular claims procedure under this part.

(b) When a carrier which participates in a transportation movement, but did not collect the transporation charges, finds that an overpayment has been made, that carrier shall immediately notify the collecting carrier. When the collecting carrier (when single or joint line haul) discovers or is notified by such a participating carrier that an overcharge, duplicate payment, or overcollection exists for any tranportation charge which has not been the subject of a claim, the carrier shall create a file as if a claim had been submitted and shall record in the file the date it discovered or was notified of the overpayment. The carrier that collected the charges shall then refund the amount of the overpayment to the person who paid the transportation charges or to the person that made duplicate payment within 30 days from the date of such discovery or notification.